WO2022223041A1

WO2022223041A1 - Sensing device

Info

Publication number: WO2022223041A1
Application number: PCT/CN2022/088598
Authority: WO
Inventors: 周文兵; 邓文俊; 袁永帅; 黄雨佳; 齐心; 廖风云
Original assignee: 深圳市韶音科技有限公司
Priority date: 2021-04-23
Filing date: 2022-04-22
Publication date: 2022-10-27
Also published as: CN116491129A; US20230353932A1; US20230362524A1; CN115243176A; CN218162856U; CN115243151A; CN116530094A; WO2022222317A1; TW202242846A; CN117044239A; CN218920578U; CN116635699A; WO2022222315A1; US20230358601A1; WO2022222316A1; CN115243133A; CN115243169A; CN115243178A; TW202243297A; CN115243149A

Abstract

A sensing device (2500), comprising: a housing (2510), an accommodating cavity being provided inside the housing (2510); a transduction unit (2520) comprising a vibration pickup structure (2521) used for picking up electric signals generated by vibration of the housing (2510), wherein the transduction unit (2520) divides the accommodating cavity into a front cavity (2530) and a rear cavity (2540) located on opposite sides of the vibration pickup structure (2521), and at least one of the front cavity (2530) or the rear cavity (2540) is filled with liquid, and the liquid is contact with the vibration pickup structure (2521); and one or more duct structures (2550), each duct structure (2550) being configured to communicate the accommodating cavity with the exterior of the housing (2510), and the liquid being at least partially located in the one or more duct structures (2550).

Description

a sensing device

priority information

This application claims priority to Chinese application No. 202110445739.3 filed on April 23, 2021, the entire contents of which are incorporated herein by reference.

technical field

This specification relates to the field of sensors, and in particular, to a sensing device.

Background technique

The sensing device is a device that receives an external vibration signal and converts the external vibration signal into an electrical signal through a transducer unit. The pickup effect of the sensing device on vibration often depends on the responsiveness of the transducer unit to the vibration signal. Although the transducer unit can provide a natural resonant frequency that is closely related to its structure, material and other physical properties, the natural resonant frequency is often not within the ideal frequency range, thus limiting the application of the sensing device in different application scenarios. For example, in some application scenarios, the sensing device may be required to provide higher responsiveness to vibration signals in a certain or certain frequency range, or to provide different responsiveness to vibration signals of different frequencies, but the inherent It is difficult for the resonant frequency to meet these requirements.

SUMMARY OF THE INVENTION

An embodiment of the present specification provides a sensing device, including: a casing, with a accommodating cavity inside; a transducer unit including a vibration pickup structure for picking up vibration of the casing to generate an electrical signal, the The transducer unit is separated in the accommodating cavity to form a front cavity and a rear cavity located on opposite sides of the vibration pickup structure, wherein at least one cavity in the front cavity or the rear cavity is filled with liquid, and the a liquid in contact with the vibration pickup structure; and one or more conduit structures, each conduit structure configured to communicate the containment cavity with the exterior of the housing, the liquid at least partially located in the one or in multiple pipeline structures.

In some embodiments, the resonance system corresponding to the one or more conduit structures causes the sensing device to generate at least one resonance peak and resonance valley.

In some embodiments, the vibration pickup structure has a first resonance frequency, and the resonance frequency of the resonance system corresponding to at least one of the one or more pipe structures is lower than the first resonance frequency.

In some embodiments, the one or more duct structures include a plurality of duct structures having different cavity volumes.

In some embodiments, a gas-liquid interface is formed between the liquid in the one or more conduit structures and the gas outside the housing.

In some embodiments, a first membrane structure is included between the liquid in the one or more conduit structures and the gas outside the housing.

In some embodiments, the vibration pickup structure includes a piezoelectric film, and the transducer unit further includes a base body, the base body is a structure body with an open opening, and the piezoelectric film covers the opening of the base body , one end of the base body away from the piezoelectric film is connected to the casing.

In some embodiments, the vibration pickup structure includes a plurality of piezoelectric beams, the transducer unit further includes a base body, and the base body is a structural body with an open opening, and each piezoelectric beam is connected to the base body respectively. connected and extending toward the center of the opening.

In some embodiments, the multiple piezoelectric beams have the same structure and are symmetrically distributed along the geometric center of the opening.

In some embodiments, barrier structures are included that fill or cover gaps between the plurality of piezoelectric beams.

In some embodiments, the gap between two adjacent piezoelectric beams in the plurality of piezoelectric beams is not greater than 20um.

In some embodiments, the transducing unit further includes a base body, the base body is a structure body with an open opening; the vibration pickup structure includes: a plurality of piezoelectric beams, and the plurality of piezoelectric beams are distributed at intervals at the opening; and a second membrane structure, the second membrane structure covers the opening of the base body, and one end of the base body away from the second membrane structure is connected to the casing.

In some embodiments, the plurality of piezoelectric beams vibrate to generate resonant peaks of different frequencies.

In some embodiments, the transducer unit includes a capacitive transducer including at least a perforated back plate and a diaphragm.

In some embodiments, the capacitive transducer further includes a washer located between the back plate and the diaphragm to space the back plate and the diaphragm.

In some embodiments, the liquid can penetrate between the perforated back plate and the diaphragm through holes in the perforated back plate.

In some embodiments, an air domain exists between the perforated back plate and the diaphragm.

In some embodiments, the housing further has a first gas cavity, one of the front cavity and the rear cavity is filled with the liquid, and the first gas cavity is connected to the front cavity and all the rear cavity. The back cavity is connected with the cavity filled with the liquid.

In some embodiments, the housing further has a second gas cavity, one of the front cavity and the rear cavity is filled with the liquid, and the second gas cavity is connected to the front cavity and all the rear cavity. The rear cavity is communicated with another cavity that is not filled with the liquid.

In some embodiments, one of the front cavity and the rear cavity is filled with the liquid, and a corresponding cavity of the front cavity and the rear cavity is not filled with the liquid The position of the casing is provided with air holes.

In some embodiments, the air hole is covered with a third membrane structure.

Description of drawings

FIG. 1 is a schematic diagram of an exemplary sensing device according to some embodiments of the present specification;

FIG. 2 is a schematic structural diagram of an exemplary microphone according to some embodiments of the present specification;

3 is a schematic diagram of an exemplary equivalent vibration model of a transducing unit according to some embodiments of the present specification;

4 is a schematic diagram of a displacement resonance curve of an exemplary sensing device according to some embodiments of the present specification;

5 is a mechanically equivalent schematic diagram of an exemplary sensing device according to some embodiments of the present specification;

6 is a schematic diagram of a liquid-filled sensing device according to some embodiments of the present specification;

7 is a mechanically equivalent schematic diagram of an exemplary sensing device according to some embodiments of the present specification;

8 is a schematic diagram of a sensing device filled with liquid and air bubbles according to some embodiments of the present specification;

FIG. 9 is an exemplary frequency response curve of a

sensing device

500 or 700 according to some embodiments of the present specification;

FIG. 10 is an exemplary frequency response curve of a

sensing device

500 or 700 according to some embodiments of the present specification;

11 is a schematic diagram of a sensing device to be filled with liquid according to some embodiments of the present specification;

12 is a schematic diagram of an exemplary liquid-filled sensing device according to some embodiments of the present specification;

13 is a frequency response curve of a sensing device before and after being partially filled with liquid according to some embodiments of the present application;

FIG. 14 is a frequency response curve before and after filling a liquid in the sensing device of the small-sized accommodating cavity according to some embodiments of the present specification;

15 is a frequency response curve of a sensor device with a large-sized accommodating cavity that is not filled with liquid and partially filled with liquid or an oil film exists in the accommodating cavity according to some embodiments of the present specification;

16 is a schematic diagram of a sensing device filled with liquid and air bubbles according to some embodiments of the present specification;

FIG. 17 is a frequency response curve of a sensing device containing bubbles of different sizes in the liquid filled in the accommodating cavity according to some embodiments of the present specification;

18A, 18B, 18C and 18D are schematic diagrams of sensing devices for different positions of air bubbles in the filling liquid according to some embodiments of the present specification;

FIG. 19 is a frequency response curve of air bubbles in the filling liquid at different positions in the accommodating cavity of the sensing device according to some embodiments of the present specification;

FIG. 20 is a frequency response curve before and after filling a liquid in a sensing device according to some embodiments of the present specification;

21 is a schematic diagram of an exemplary droplet-containing sensing device according to some embodiments of the present specification;

22 is a schematic diagram of an exemplary droplet-containing sensing device according to some embodiments of the present specification;

23A is a schematic diagram of an exemplary sensing device comprising a liquid film according to some embodiments of the present specification;

23B is a schematic diagram of an exemplary sensing device comprising a liquid film according to some embodiments of the present specification;

24A is a schematic diagram of an exemplary sensing device comprising a liquid film according to some embodiments of the present specification;

24B is a schematic diagram of an exemplary sensing device comprising a liquid film according to some embodiments of the present specification;

FIG. 25 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

Figure 26A is a schematic diagram of a plurality of pipeline structures according to some embodiments of the present specification;

Figure 26B is a schematic diagram of a plurality of pipeline structures according to some embodiments of the present specification;

27 is a mechanically equivalent schematic diagram of a sensing device according to some embodiments of the present specification;

FIG. 28 is a frequency response curve of a sensing device according to some embodiments of the present specification;

FIG. 29A is a schematic diagram of the vibration direction of the sensing device according to some embodiments of the present specification at the resonance peak;

29B is a schematic diagram of the vibration direction of the sensing device according to some embodiments of the present specification when it is in a resonance valley;

FIG. 30 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

Figure 31A is a schematic structural diagram of part A in Figure 25;

Figure 31B is a schematic structural diagram of part A in Figure 25;

32A is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification;

32B is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification;

33 is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification;

34A is a cross-sectional view of B-B in FIG. 33 according to some embodiments of the present specification;

34B is a cross-sectional view of B-B in FIG. 33 according to some embodiments of the present specification;

34C is a cross-sectional view of B-B in FIG. 33 according to some embodiments of the present specification;

34D is a cross-sectional view of B-B in FIG. 33 according to some embodiments of the present specification;

FIG. 35A is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

35B is a schematic structural diagram of a vibration pickup structure according to some embodiments of the present specification;

36A is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 36B is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 37 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 38 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

Figure 39 is a frequency response curve of a sensing device according to some embodiments of the present specification;

FIG. 40 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 41 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 42 is a schematic structural diagram of a sensing device according to some embodiments of the present specification;

FIG. 43 is a schematic structural diagram of a sensing device according to some embodiments of the present specification.

Detailed ways

In order to illustrate the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without any creative effort, the present application can also be applied to the present application according to these drawings. other similar situations. Unless obvious from the locale or otherwise specified, the same reference numbers in the figures represent the same structure or operation.

It is to be understood that "system", "device", "unit" and/or "module" as used herein is a method used to distinguish different components, elements, parts, parts or assemblies at different levels. However, other words may be replaced by other expressions if they serve the same purpose.

As shown in this application and in the claims, unless the context clearly dictates otherwise, the words "a", "an", "an" and/or "the" are not intended to be specific in the singular and may include the plural. Generally speaking, the terms "comprising" and "comprising" only imply that the clearly identified steps and elements are included, and these steps and elements do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

The embodiments of this specification describe a sensing device. In some embodiments, the sensing device may include a housing with a accommodating cavity inside. In some embodiments, the sensing device may further include a transducer unit, and the transducer unit may include a vibration pickup structure for picking up the vibration of the housing to generate an electrical signal. The transducer unit can receive the vibration of the casing and convert it into an electrical signal for output. In some embodiments, the transducer unit may be separated in the accommodating cavity to form a front cavity and a rear cavity located on opposite sides of the vibration pickup structure, at least one of the front cavity or the rear cavity is filled with liquid, and the liquid and the vibration pickup structure touch. In some embodiments, the sensing device may further include one or more conduit structures, each conduit structure may be configured to communicate the containment cavity with the exterior of the housing, the liquid at least partially located in the one or more conduit structures . For easy understanding, the housing and the transducer unit can be regarded as a sensor, wherein the vibration of the vibration pickup structure has a first resonance frequency, that is, the frequency response curve of the vibration pickup structure has a first resonance peak at the first resonance frequency. The liquid in the fluid region corresponding to each pipe structure (including the interior of the cavity of the pipe structure and the fluid region close to the pipe structure, see FIG. 25 and related descriptions for details) and the outside of the casing to which the pipe structure is connected (for example, the casing The air outside the body) can be approximately regarded as a resonant system added to the sensor, so that the frequency response curve of the sensing device has additional resonant peaks and resonant valleys on the basis of the first resonant peak. In some embodiments, the resonance frequency corresponding to the resonance peak and the resonance valley is lower than the first resonance frequency, so that the response of the sensing device in the frequency range before the first resonance peak appears on the frequency response curve is greatly improved. In some embodiments, when the conduit structure may include multiple conduit structures, the multiple conduit structures correspond to multiple resonance systems, and the multiple resonance systems may additionally provide multiple additional resonance peaks and resonance valleys for the sensor. In some embodiments, at least one of the resonance frequencies corresponding to the plurality of resonance peaks and resonance valleys is less than the first resonance frequency. In some embodiments, the resonance system corresponding to the pipe structure can be applied to different types of sensors (eg, piezoelectric sensors, capacitive sensors, electrodynamic sensors, eddy current sensors, inductive sensors), so that the sensor's The frequency response curve has multiple resonance peaks and resonance valleys, thereby improving the frequency response of the sensor in a frequency range less than the first resonance frequency. Further, by setting different pipeline structures, it is possible to make a large difference between the multiple resonance peaks and the resonance valleys, that is, a large Q value. In this way, when the sensing device collects the vibration signal, it will show different sensitivities to the vibration signal of different frequency components, and the generated electrical signal will appear as the fusion of multiple "subband" signals. In the back-end circuit or algorithm, only the low-order filter can be used to intercept the molecular band signal with a steeper boundary. In some embodiments, the sensing devices referred to in this specification may be applied as inertial sensors. In some embodiments, the sensing device may be applied to common scenarios of inertial sensors such as accelerometers, energy harvesters, and gyroscopes. In some embodiments, the sensing device may also be applied to audio equipment such as bone conduction microphones, speakers, and hearing aids, so as to improve the sensitivity of the audio equipment. In some embodiments, the sensing device may also be applied to audio-enabled electronic devices (eg, headphones, glasses, smart helmets, speakers, tablets, cell phones, etc.).

FIG. 1 is a schematic diagram of an exemplary sensing device shown in accordance with some embodiments of the present specification.

The sensing device 100 may generate deformation and/or displacement based on external signals, such as mechanical signals (eg, pressure, mechanical vibration), acoustic signals (eg, sound waves), electrical signals, optical signals, thermal signals, and the like. The deformations and/or displacements may be further converted into target signals by the transducer components of the sensing device 100 . In some embodiments, the target signal may be an electrical signal, a mechanical signal (eg, mechanical vibration), an acoustic signal (eg, a sound wave), an electrical signal, an optical signal, a thermal signal, or the like. In some embodiments, the sensing device 100 may be a microphone (eg, an air conduction microphone or a bone conduction microphone), a speaker (eg, an air conduction speaker or a bone conduction speaker), an accelerometer, a pressure sensor, a hydrophone, an energy harvester device, gyroscope, etc. An air conduction microphone or air conduction speaker is a microphone or speaker in which sound waves are conducted through the air. A bone conduction microphone or bone conduction speaker refers to a microphone or speaker in which sound waves are conducted in a solid body (eg, bone) in a mechanically vibrating manner.

Illustratively, as shown in FIG. 1, the sensing device 100 may include a housing 110, a transducer unit 120, and a processor 130 (eg, an integrated circuit (IC)).

The housing 110 may be a regular or irregular three-dimensional structure with an accommodating cavity (ie, a hollow portion) inside, for example, may be a hollow frame structure, including but not limited to a rectangular frame, a circular frame, a regular polygonal frame, etc. shape, and any irregular shape. The housing 110 may be used to accommodate the transducer unit 120 and/or the processor 130 . In some embodiments, the housing 110 may adopt one or more packaging methods such as plastic packaging and metal packaging. In some embodiments, the accommodating cavity of the housing 110 may contain one or more of gas, liquid, solid and the like. In some embodiments, the accommodating cavity may also be a vacuum structure.

The transducer unit 120 may be located in the accommodating cavity of the housing 110 or at least partially suspended in the accommodating cavity of the housing 110 . The transducer unit 120 may be used to convert the external signal into the target signal. Taking a bone conduction microphone (also called a vibration sensing device) as an example, the external signal is a mechanical vibration signal, and the target signal is an electrical signal. The transducing unit 120 may include a vibration pickup structure. The vibration pickup structure may have certain elasticity. For example, the vibration pickup structure may be a vibrating rod (eg, a cantilever beam), a vibrating membrane (eg, a piezoelectric membrane), a vibrating block, and the like. The vibration pickup structure may deform and/or displace in response to the mechanical vibration signal. The transducer unit 120 may convert the deformation and/or displacement into a target signal (eg, an electrical signal). In some embodiments, the transducing unit 120 may include piezoelectric transducers, acoustic transducers, electromagnetic transducers, capacitive transducers, and the like. In some embodiments, the transducer unit 120 may be electrically connected to the processor 130 through leads 140 .

The processor 130 may be configured to process data and/or signals. In some embodiments, the processor 130 may include bipolar integrated circuits (eg, logic gates, emitter-coupled logic circuits, etc.), unipolar integrated circuits (eg, FET-type integrated circuits, n-channel FETs, etc.) one or more of integrated circuits, etc.)

In some embodiments, the processor 130 may be located in the accommodating cavity of the housing 110 or at least partially suspended in the accommodating cavity of the housing 110 . In some embodiments, the processor 130 may also be located outside the accommodating cavity of the housing 110 . For example, the processor 130 may be disposed on the outer surface of the housing 110, which may be signally connected to the transducer unit 120 through wires. In some embodiments, the processor 130 may process the target signal. Continuing to take the bone conduction microphone as an example, the processor 130 may convert the target signal into voice data, or send the target signal or voice data corresponding to the target signal to the cloud and/or other terminal devices. In some embodiments, the transducer unit 120 and the processor 130 may be arranged in parallel (as shown in FIG. 1 ), arranged above and below, or internally integrated.

In some embodiments, sensing device 100 may also include leads 140 . Leads 140 may be used to signally connect the transducer unit 120 and the processor 130 . For example, leads 140 may transmit target signals or other signals (eg, configuration instructions, acquisition instructions, etc.). In some embodiments, the lead 140 may not be necessary, and its function may be achieved by other connection methods. For example, the transducing unit 120 and the processor 130 may be stacked on top of each other, and the transducing unit 120 and the processor 130 may transmit data in a manner in which their ports are in direct contact, instead of the function of the lead 140 .

FIG. 2 is a schematic structural diagram of an exemplary microphone according to some embodiments of the present specification.

As shown in FIG. 2 , the microphone 200 may include a housing 210 , a transducer unit 220 , a processor 230 and a printed circuit board (PCB) 240 .

The PCB 240 can be a phenolic PCB paper substrate, a composite PCB substrate, a glass fiber PCB substrate, a metal PCB substrate, a build-up multilayer PCB substrate, and the like. In some embodiments, the PCB 240 may be an FR-4 grade fiberglass PCB substrate made of epoxy fiberglass cloth. Circuits and other components of the microphone 200 may be provided on the PCB 240 (eg, by means of laser etching, chemical etching, etc.). In some embodiments, PCB 240 may also be a flexible printed circuit board (FPC). In some embodiments, the transducer unit 220 and the processor 230 are fixedly connected to the PCB 240 through the transducer unit fixing glue 250 and the processor fixing glue 260, respectively. In some embodiments, the transducer unit fixing glue 250 and/or the processor fixing glue 260 may be conductive glue (eg, conductive silver glue, copper powder conductive glue, nickel-carbon conductive glue, silver-copper conductive glue, etc.). The conductive adhesive may be conductive glue, conductive adhesive film, conductive rubber ring, conductive tape, and the like. The transducer unit 220 and/or the processor 230 are respectively electrically connected with other components through circuits provided on the PCB 240. The transducer unit 220 and the processor 230 may be directly connected by wires 270 (eg, gold wires, copper wires, aluminum wires, etc.).

The housing 210 can be a regular or irregular three-dimensional structure with a cavity (ie a hollow part) inside, for example, can be a hollow frame structure, including but not limited to a rectangular frame, a circular frame, a regular polygon frame and other regular shapes , and any irregular shape. The housing 210 is covered above the PCB 240, and seals the transducer unit 220, the processor 230, the PCB 240 and the circuits and other components provided thereon. The housing 210 can be made of metal (eg, stainless steel, copper, etc.), plastic (eg, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and acrylonitrile-butadiene ethylene-styrene copolymer (ABS), etc.), composite materials (such as metal matrix composite materials or non-metal matrix composite materials), etc. In some embodiments, the material used for housing 210 is brass.

The transducer unit 220 may convert the external vibration signal into an electrical signal. Taking a bone conduction microphone as an example, the transducer unit 220 may include a base structure, a laminated structure (ie, a vibration pickup structure) and at least one damping structure layer. In some embodiments, the base structure and the laminated structure may be located in the shell 210 of the bone conduction microphone, the base structure is fixedly connected to the inner wall of the shell 210, and the laminated structure is carried by the base structure. In some embodiments, at least a portion of the laminate structure is physically connected to the base structure. The "connection" mentioned in this application can be understood as the connection between different parts on the same structure, or after preparing different components or structures, the independent components or structures are welded, riveted, clamped, bolted, glued or by means of physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition), the first part or structure is deposited on the second part or structure . In some embodiments, at least part of the laminated structure can be fixed to the upper surface or the lower surface of the base structure, and at least part of the laminated structure can also be fixed to the sidewall of the base structure. For example, the laminated structure can be a cantilever beam (also known as a piezoelectric beam), which can be a plate-like structure, and one end of the cantilever beam is located with the upper surface, the lower surface of the base structure, or the cavity of the base structure. The side walls are connected, and the other end of the cantilever beam is not connected or in contact with the base structure, so that the other end of the cantilever beam is suspended in the cavity of the base structure. For another example, the bone conduction microphone may include a diaphragm layer (also called a suspended diaphragm structure), the suspended diaphragm structure is fixedly connected to the base structure, and the laminated structure is disposed on the upper surface or the lower surface of the suspended diaphragm structure. For another example, the laminated structure may include a mass element and one or more support arms, the mass element is fixedly connected to the base structure through one or more support arms, one end of the support arm is connected to the base structure, and the other end of the support arm is connected to the mass. The elements are connected, so that the mass element and the partial area of the support arm are suspended in the cavity of the base structure. It should be noted that, "located in the cavity" or "suspended in the cavity" in this application may mean suspended in the interior, lower part or above of the cavity.

In some embodiments, the laminated structure may include a vibration unit and a signal conversion unit (which may also be referred to as an acoustic transduction unit). The vibration unit refers to the part of the laminated structure that is easily deformed by external force, and the vibration unit can be used to transmit the deformation caused by the external force to the signal conversion unit. The signal conversion unit refers to the part of the laminated structure that converts the deformation of the vibration unit into an electrical signal. Specifically, the base structure can generate vibration based on an external vibration signal, the vibration unit is deformed in response to the vibration of the base structure; the signal conversion unit generates an electrical signal based on the deformation of the vibration unit. It should be known that the description of the vibration unit and the signal conversion unit here is only for the purpose of conveniently introducing the working principle of the laminated structure, and does not limit the actual composition and structure of the laminated structure. In some embodiments, the vibration unit may not be necessary, and its function may be completely realized by the signal conversion unit. The signal conversion unit may generate an electrical signal in direct response to the vibration of the base structure. For example, the signal conversion unit may be a piezoelectric cantilever beam.

In some embodiments, the vibration unit and the signal conversion unit are overlapped to form a stacked structure. The signal conversion unit may be located on the upper layer of the vibration unit, and the signal conversion unit may also be located at the lower layer of the vibration unit.

In some embodiments, the signal conversion unit may include at least two electrode layers (eg, a first electrode layer and a second electrode layer) and a piezoelectric layer, and the piezoelectric layer may be located between the first electrode layer and the second electrode layer . Piezoelectric layer refers to a structure that can generate voltage on both ends of the piezoelectric layer when subjected to external force. In some embodiments, the piezoelectric layer can generate a voltage under the action of the deformation stress of the vibration unit, and the first electrode layer and the second electrode layer can collect the voltage (electrical signal).

Taking a bone conduction microphone as an example, the vibration unit may include at least one elastic layer. The signal conversion unit may include a first electrode layer, a piezoelectric layer and a second electrode layer arranged in sequence from top to bottom, the elastic layer is located on the surface of the first electrode layer or the second electrode layer, and the elastic layer can deform during the vibration process , the piezoelectric layer generates an electrical signal based on the deformation of the elastic layer, and the first electrode layer and the second electrode layer can collect the electrical signal. For illustrative purposes only, the vibrating unit may include a first elastic layer and a second elastic layer sequentially arranged from top to bottom. The first elastic layer and the second elastic layer may be plate-like structures made of semiconductor materials. In some embodiments, the semiconductor material may include silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, and the like. In some embodiments, the materials of the first elastic layer and the second elastic layer may be the same or different.

In some embodiments, the piezoelectric layer may be a piezoelectric polymer film obtained by a semiconductor deposition process (eg, magnetron sputtering, MOCVD). In some embodiments, the material of the piezoelectric layer may include piezoelectric crystal material and piezoelectric ceramic material. Piezoelectric crystal refers to a piezoelectric single crystal. In some embodiments, the piezoelectric crystal material may include crystal, sphalerite, boronite, tourmaline, hematite, GaAs, barium titanate and derivatives thereof, KH ₂ PO ₄ , NaKC ₄ H ₄ O ₆ · 4H ₂ O (roshi salt), etc., or any combination thereof. Piezoelectric ceramic materials refer to piezoelectric polycrystals formed by random collection of fine crystal grains obtained by solid-phase reaction and sintering between powders of different materials. In some embodiments, the piezoelectric ceramic material may include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN) ), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the piezoelectric layer material may also be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF), or the like. In some embodiments, the first electrode layer and the second electrode layer are conductive material structures. Exemplary conductive materials may include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metal and alloy materials may include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, or any combination thereof. In some embodiments, the alloy material may include copper-zinc alloy, copper-tin alloy, copper-nickel-silicon alloy, copper-chromium alloy, copper-silver alloy, etc., or any combination thereof. In some embodiments, the metal oxide material may include RuO ₂ , MnO ₂ , PbO ₂ , NiO, etc., or any combination thereof.

The damping structural layer may refer to a structural body with damping properties. In some embodiments, the damping structure layer may be a film-like structure or a plate-like structure. Further, at least one side of the damping structure layer may be connected to the base structure. In some embodiments, the damping structure layer may be located between the upper and/or lower surfaces of the laminate structure or between the multi-layered layered structures of the laminate structure. For example, when the laminated structure is a cantilever beam, the damping structure layer may be located on the upper surface and/or the lower surface of the cantilever beam. For another example, when the laminated structure is a support arm and a mass element, when the mass element protrudes downward relative to the support arm, the damping structure layer may be located on the lower surface of the mass element and/or the upper surface of the support arm. In some embodiments, for macro-sized laminate structures and base structures, the damping structural layer may be directly bonded at the base structure or the laminate structure. In some embodiments, for microelectromechanical systems (MEMS) devices, semiconductor processes, such as evaporation, spin coating, microfabrication, etc., can be used to connect the damping structure layer to the laminate structure and the base structure. In some embodiments, the shape of the damping structure layer may be a regular or irregular shape such as a circle, an ellipse, a triangle, a quadrangle, a hexagon, an octagon, and the like. In some embodiments, the output effect of the electrical signal of the bone conduction microphone can be improved by selecting the material, size, thickness, etc. of the damping structure layer.

When the shell 210 of the bone conduction microphone is vibrated by an external force (for example, the vibration of the face of the human body drives the shell 210 to vibrate), the vibration of the shell 210 drives the vibration of the base structure. ) have different properties, so that the laminated structure and the casing 210 cannot keep a completely consistent movement, thereby generating relative motion, which in turn causes the vibration unit of the laminated structure to deform. Further, when the vibration unit is deformed, the piezoelectric layer of the signal conversion unit is subjected to the deformation stress of the vibration unit to generate a potential difference (voltage), and at least two electrode layers ( For example, the first electrode layer and the second electrode layer) can collect the potential difference to convert the external vibration signal into an electrical signal.

The damping of the damping structural layer is different under different stress (deformation) states, for example, it exhibits larger damping at high stress or large amplitude. Therefore, the characteristics of the laminated structure with small amplitude in the non-resonant area and large amplitude in the resonant area can be used. By adding a damping structure layer, the sensitivity of the bone conduction microphone in the non-resonant area can be reduced, and the quality factor Q value of the resonant area can be reduced, so that the The frequency response of bone conduction microphones is flat over the entire frequency band. The bone conduction microphone can be applied to earphones (eg, bone conduction earphones or air conduction earphones), glasses, virtual reality devices, helmets, etc. The bone conduction microphone can be placed on the head (eg, face), neck, ears, and At positions such as the top of the head, the bone conduction microphone can pick up the vibration signal of the bone when a person speaks, and convert it into an electrical signal to collect sound. It should be noted that the base structure is not limited to a structure independent of the shell 210 of the bone conduction microphone, and in some embodiments, the base structure may also be a part of the shell 210 of the bone conduction microphone.

The processor 230 may acquire the electrical signal from the transducer unit 220 and perform signal processing. In some embodiments, the signal processing may include frequency modulation processing, amplitude modulation processing, filtering processing, noise reduction processing, and the like.

3 is a schematic diagram of an exemplary equivalent vibration model of a transducing unit according to some embodiments of the present specification.

The transducer unit 120 can be simplified and equivalent to the mass-spring-damping system shown in FIG. 3 . The mass-spring-damping system is forced to vibrate under the action of the exciting force F. The motion of the system can be described by the following differential equation:

Among them, M is the mass of the system, R is the damping of the system, K is the elastic coefficient of the system, F is the amplitude of the driving force, x is the displacement of the system, and ω is the circular frequency of the external force. Solving the above equation for steady-state displacement, we get:

x=x _a cos(ωt-θ), (2)

in,

When the sensing device 100 actually works, x corresponds to the deformation amount of the vibration-electrical signal conversion module of the transducer unit 120 , and the magnitude of x finally corresponds to the magnitude of the electrical signal output. The displacement amplitude ratio (normalized) is:

in,

is the mechanical quality factor;

is the static displacement amplitude (or the displacement amplitude when ω=0); ω ₀ is the system resonant frequency.

4 is a schematic diagram of a displacement resonance curve of an exemplary sensing device shown in accordance with some embodiments of the present specification. The normalized displacement resonance curve of the sensor device 100 composed of transducer units with different parameters (elastic coefficient, mass, damping) is shown in FIG. 4 . The horizontal axis corresponds to the ratio of the frequency of the external force (or vibration) to the resonance frequency of the system

The vertical axis corresponds to the A value of formula (3). It can be seen that for different sensing devices 100, the transducer units 120 are different and have different values of the mechanical quality factor Q _m , and corresponding to different curves in the figure, their displacements A are different. The ratio of the frequency of the external force (or vibration) to the resonant frequency of the system

is 1, the system resonance occurs, and the displacement change is the largest at this time. For a transducer unit with a larger Q _m value, the larger the A value, the steeper the curve; and for a transducer unit with a smaller Q _m value, the smaller the A value, the flatter the curve, so the quality factor of the transducer unit 120 can be adjusted by adjusting the quality factor of the transducer unit 120. Q _m value (eg change its structure), adjust the Q value.

The principle of the microphone generating the voltage signal is that the vibration-electrical signal conversion module (that is, the transducer unit) and the microphone shell produce relative displacement (for example, the electret microphone is deformed by the diaphragm, changing the distance from the substrate to form a voltage signal; cantilever beam type The bone conduction microphone is deformed by the cantilever vibration device to generate a piezoelectric effect, thereby forming an electrical signal), and the greater the displacement, the greater the output signal. Obviously, the vibration-electrical signal conversion module of the microphone completely conforms to the displacement resonance curve as shown in Figure 4.

when reducing

, the resonant frequency of the system decreases. When the resonant frequency is changed, the sensitivity of the signal before the resonant frequency increases, but after the resonant frequency, the sensitivity of the signal decreases at a certain frequency. When adjusting the sensitivity by adjusting the resonant frequency of the sensor device 100, the frequency range needs to be taken into consideration. In some embodiments, the resonant frequency of the sensing device 100 is between 1500 Hz-6000 Hz. In some embodiments, the resonant frequency of the sensing device 100 is between 1500 Hz-3000 Hz. In some embodiments, the resonant frequency of the sensing device 100 is between 2000 Hz-2500 Hz.

5 is a mechanically equivalent schematic diagram of an exemplary sensing device shown in accordance with some embodiments of the present specification.

In some embodiments, the sensing device 500 may include a transducing unit 520 and an additional resonant system 530 (also referred to as the first resonant system 530). In some embodiments, the sensing device 500 can be regarded as adding the first resonance system 530 on the basis of the transducer unit 520 . Exemplarily, in this embodiment, the first resonance system 530 may be a spring (K _m4 )-mass (M _m4 )-damping (R _m4 ) system. The first resonance system 530 may be coupled between the housing (not shown in the figure) and the transducer unit 520 . Due to the action of the first resonance system 530, when the casing receives an external vibration signal, the external vibration signal will be transmitted to the transducer through the casing area connected with the transducer unit 520 and the casing area connected with the first resonance system 530 respectively. unit 520. Therefore, the mechanical response of the sensing device 500 is changed compared to the sensing device 100 . Accordingly, the electrical, acoustic and/or thermal response of sensing device 500 is changed compared to sensing device 100 .

In some embodiments, the first resonance system 530 may be formed by filling the housing cavity with liquid. For example, the liquid fills the accommodating cavity in the housing, and the transducing unit 520 is wrapped in the liquid.

6 is a schematic diagram of a liquid-filled sensing device according to some embodiments of the present specification. As shown in FIG. 6 , the liquid 610 can be selected from a liquid with safety properties (eg, non-flammable and non-explosive) and stable properties (eg, non-volatile, no high temperature deterioration, etc.). For example, the liquid 610 may include oil (eg, silicone oil, glycerin, castor oil, motor oil, lubricating oil, hydraulic oil (eg, aviation hydraulic oil), etc.), water (including pure water, aqueous solutions of other inorganic or organic substances, etc. (eg, brine) ), oil-water emulsion, or other liquids that meet their performance requirements, or a combination of one or more of them.

The density and kinematic viscosity of the liquid 610 are within a certain density range and kinematic viscosity range, respectively. In some embodiments, the density range and kinematic viscosity range may be set by the user or based on the performance of the sensing device 500 (eg, sensitivity, noise floor level, peak-to-peak resonance, frequency range of resonance peaks, peak-to-valley, and/or quality factor Q, etc.) to determine. In some embodiments, the liquid 610 can be selected from silicone oil. Silicone oil has the characteristics of high temperature resistance, non-volatile, wide viscosity range, density of about 0.94kg/m ³ , and a wide range of optional kinematic viscosity (for example, 0.1-1000 stokes (cst)).

The liquid 610 may be injected into the accommodating cavity of the housing 510 in a specific manner. For the specific description of injecting the liquid 610 into the accommodating cavity of the housing 510, reference may be made to other parts of the specification of this application, such as FIG. 11 and its description.

In some embodiments, the frequency response curve of the sensing device 500 includes at least two resonance peaks. The at least two resonance peaks include a first resonance peak and a second resonance peak. The resonance frequency corresponding to the first resonance peak is mainly related to the properties (eg, shape, material, structure, etc.) of the transducing unit 520 . The second resonance peak is a resonance peak generated by the action of the first resonance system 530, and its corresponding resonance frequency is mainly related to one or more mechanical parameters of the first resonance system 530 (for example, the equivalent spring (K _m4 ) of the resonance system, the mass (M _m4 ), damping (R _m4 ), etc.). In order to make the sensing device 500 suitable for different scenarios, the resonance frequency corresponding to the first resonant peak (also referred to as the first resonant frequency) and the resonant frequency corresponding to the second resonant peak (also referred to as the second resonant frequency) Different relationships can be satisfied. For example, the second resonant frequency may be less than, equal to, or greater than the first resonant frequency.

For the purpose of illustration only, due to the existence of the second resonance peak corresponding to the first resonance system 530, the frequency response curve of the sensing device 500, especially in the middle and low frequency bands where voice information is rich, will be improved, so that the frequency response curve of the sensing device 500 is improved. Sensitivity has improved. In addition, since the first resonance system 530 acts on the transducer unit 520 , the vibration characteristics of the sensing device 500 will be changed compared with those without the first resonance system 530 . Specifically, the first resonance system 530 acts on the transducer unit 520, which can affect the mass, stiffness and/or damping of the sensing device 500, and the effect is equivalent to making the Q value of the first resonance peak of the sensing device 500 relative to The Q value of the sensing device not connected to the first resonant system 530 is changed (eg, the Q value is decreased). For more specific descriptions of the frequency response curve and the first resonance peak and the second resonance peak of the sensing device 500, reference may be made to other places in the specification of this application, such as FIG. 9 and FIG. 10 and their descriptions.

In some embodiments, the first resonance system 530 can reduce the external impact received by the transducing unit 520 to protect the transducing unit 520 . For example, if the first resonance system 530 is the liquid 610 that fills the accommodating cavity of the sensing device 500, because the liquid 610 has a viscous effect, and the liquid 610 has a much smaller stiffness than the device material, the sensing device 500 can be improved to receive external shocks Reliability under load (for example, bone conduction microphones are required to withstand shocks of 10,000g acceleration without damage). Specifically, due to the viscous effect of the liquid 610, part of the impact energy can be absorbed and consumed, so that the impact load on the transducing unit 520 is greatly reduced.

In addition, the sensing device 100 is often deformed, such as bending (along the length, width), torsion, etc., due to the presence of stress during processing, especially for cantilever-type devices. However, cantilever beam structures are commonly used structures for sensing devices such as bone conduction microphones and acceleration. Since the housing of the sensing device 500 is filled with the liquid 610, the gravity, surface tension, viscous force, etc. of the liquid 610 can be used to correct the deformation of the device, so that the deformation of the device is smaller, the output is more stable, and it is closer to the actual design effect.

7 is a mechanically equivalent schematic diagram of an exemplary sensing device shown in accordance with some embodiments of the present specification. As shown in FIG. 7 , the sensing device 700 may include a transducer unit 720 and a second resonance system 740 . In some embodiments, the sensing device 700 can be regarded as adjusting the first resonance system 530 on the basis of the transducer unit 720 to form the second resonance system 740 . Exemplarily, in this embodiment, the second resonant system 740 newly adds a spring (K _m3 ) and a damping (R _m3 ) compared to the first resonant system 530 . The second resonance system 740 may be disposed between the housing 710 and the transducing unit 720 . For example, as shown in FIG. 7 , the spring (K _m3 )-damping (R _m3 ) of the second resonance system 740 may be the same as the spring (K _m4 )-mass (M _m4 )-damping (R _m4 ) of the first resonance system 530 connected in series and indirectly acting on the transducer unit 720 . For another example, the spring (K _m3 )-damping (R _m3 ) of the second resonance system 740 may be connected in series with the spring (K _m4 )-mass (M _m4 )-damping (R _m4 ) of the first resonance system 530 and act directly in the transducer unit 720 . Due to the action of the second resonance system 740, when the casing 710 receives an external vibration signal, the external vibration signal will pass through the casing area connected to the transducer unit 720 and the casing area connected with the second resonance system 740 through the second The resonant system 740 is delivered to the transducing unit 720 . Therefore, the mechanical response of the sensing device 700 is changed compared to the sensing device 500 . Accordingly, the electrical, acoustic, and/or thermal response of sensing device 700 is altered compared to sensing device 500 . Meanwhile, due to the newly introduced spring (K _m3 ) and damping (R _m3 ) of the second resonance system 740 , the vibration characteristics (eg, stiffness-damping, etc.) of the sensing device 700 are changed compared to the sensing device 500 .

In some embodiments, the second resonance system 740 may be formed by filling the receiving cavity of the sensing device 700 with a different medium. For example, part of the liquid can be filled into the accommodating cavity of the sensing device 700 to form a second resonance system 740 in which the liquid and air bubbles (also referred to as air cavity) coexist in the accommodating cavity. At this time, the liquid in the accommodating cavity can be equivalent to the above-mentioned spring (K _m4 )-mass (M _m4 )-damping (R _m4 ), and the air bubble can be equivalent to the above-mentioned spring (K _m3 ) and damping (R _m3 ). For another example, the accommodating cavity of the sensing device 700 may be filled with liquid, the sensing device 700 may further include a pipe structure connecting the accommodating cavity with the outside of the housing, and the liquid is at least partially located in one or more pipe structures . At this time, the liquid in the accommodating cavity can be equivalent to the above-mentioned spring (K _m4 )-mass (M _m4 )-damping (R _m4 ), and the liquid in the fluid region corresponding to the pipe structure and the air corresponding to the pipe structure can be equivalent are the above spring (K _m3 ) and damping (R _m3 ). For another example, the accommodating cavity of the sensing device 700 may be filled with liquids with different densities that are immiscible with each other to form the second resonance system 740 . In some embodiments, the medium filled into the accommodating cavity of the sensing device 700 may be set by the user or based on the performance of the sensing device 700 (eg, sensitivity, noise floor level, peak-to-peak resonance, frequency range of the resonance peak, Peak-to-valley value and/or quality factor Q, etc.) are determined.

8 is a schematic diagram of a sensing device filled with liquid and air bubbles according to some embodiments of the present specification. As shown in FIG. 8 , in the sensing device 700 , the accommodating cavity of the housing 710 is filled with liquid 810 and air bubbles 820 . The liquid 810 in the sensing device 700 may be the same or a different type of liquid as the sensing device 500 . For example, both the sensing device 700 and the sensing device 500 are filled with silicone oil with the same kinematic viscosity. For another example, the sensing device 700 and the sensing device 500 are filled with different kinds of liquids 810 or the same kind of liquids 810 with different kinematic viscosities (eg, silicone oil with a kinematic viscosity of 0.65 cst and 200 cst, respectively). The liquid 810 and the air bubbles 820 may be injected into or formed in the accommodating cavity of the housing 710 in a specific manner. Regarding the manner of injecting or forming the liquid 810 and the air bubble 820 in the accommodating cavity of the housing 710 , for details, reference may be made to the descriptions elsewhere in the specification of this application, such as FIG. 11 and its description.

In some embodiments, the frequency response curve of the sensing device 700 includes at least two resonance peaks. The at least two resonance peaks include a third resonance peak and a fourth resonance peak. The third resonance peak is the resonance peak corresponding to the transducer unit 720 , and the fourth resonance peak is the resonance peak generated by the action of the second resonance system 740 .

In some embodiments, different relationships may be satisfied between the third resonance frequency (the resonance frequency corresponding to the third resonance peak) and the fourth resonance frequency (the resonance frequency corresponding to the fourth resonance peak) of the sensing device 700 . Exemplarily, when the second resonance system 740 is jointly formed by the liquid 810 and the air bubble 820, due to the large compressibility and low stiffness of the air bubble 820 (compared to the case of the pure liquid 810), the sensing device 700 may have a low frequency. Or the resonant frequency of the mid-low frequency band. For example, the fourth resonance frequency is a low frequency or a medium low frequency, and the third resonance frequency may be greater than the fourth resonance frequency, for example, the third resonance frequency is a higher frequency band. For another example, the third resonance frequency and the fourth resonance frequency are both medium and low frequencies. In this application, low frequency, medium low frequency, and medium high frequency refer to frequencies whose frequency values are within a certain range. For example, the frequency range corresponding to the low frequency or the medium low frequency or the medium high frequency is within 7000 Hz, within 5000 Hz, within 3000 Hz, within 1000 Hz, within 500 Hz, and the like. For example, the frequency range corresponding to the higher frequency band is above 2000 Hz, above 5000 Hz, above 8000 Hz, and so on. The third resonance frequency is a higher frequency than the fourth resonance frequency. Optionally, the difference between the resonant frequencies of the two is 100-6000 Hz. When the sensing device 700 has a resonant frequency in the low frequency or middle-low frequency range, its sensitivity at low frequency is higher than that of the sensing device without the second resonance system 740; when the sensing device 700 is further at high frequency Or when the mid-high frequency has a resonant frequency, the frequency response curve is also flatter in the range between the two resonant peaks, which is more conducive to the acquisition of effective voice signals in the frequency band.

In addition, since the second resonance system 740 acts on the transducer unit 720 , the vibration characteristics of the sensing device 700 will be changed compared with the sensing device without the second resonance system 740 . Exemplarily, the second resonance system 740 acts on the transducer unit 720, which can affect the stiffness and/or damping of the sensing device 700, and the effect is equivalent to making the Q value of the third resonance peak of the sensing device 700 relative to the other. The sensing device connected to the second resonant system 740 is changed (eg, the Q value is reduced). For more specific descriptions of the frequency response curve and the third resonance peak and the fourth resonance peak of the sensing device 700, reference may be made to other places in the specification of this application, such as FIG. 9 and FIG. 10 and their descriptions.

In some embodiments, the second resonance system 740 can reduce the external impact on the transducing unit 720 to protect the transducing unit 720 . For example, if the liquid 810 and the air bubble 820 are introduced into the accommodating cavity of the housing 710, the impact reliability of the sensing device 700 when receiving an external impact load will be improved. Due to the viscous effect of the liquid 810 and the large compressibility of the gas, part of the impact energy can be absorbed and consumed, so that the impact load on the transducing unit 720 is greatly reduced.

In addition, during the processing of the sensing device 700, the device is often deformed due to the presence of stress. By injecting the liquid 810 and the air bubble 820 into the chamber, the gravity, surface tension, viscous force, etc. of the liquid 810 can be used to correct the deformation of the device, so that the deformation of the sensing device 700 is smaller, the output is more stable, and it is closer to the actual design Effect.

It should be noted that the above description of the sensing device 700 is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. It can be understood that those skilled in the art, after understanding the principle of the system, may arbitrarily combine its structures and modules, or form a subsystem to connect with other modules without departing from the principle.

FIG. 9 is an exemplary frequency response curve of a

sensing device

500 or 700 according to some embodiments of the present specification.

Exemplarily, as shown in FIG. 9 , the dashed line 910 represents the frequency response curve of the sensing device without an equivalent resonance system, and the solid line 920 represents the frequency response curve of the

sensing device

500 or 700 . The abscissa represents the frequency, in Hertz Hz, and the ordinate represents the sensitivity, in volts decibels dBV. Frequency response curve 910 includes resonance peak 911 . The frequency response curve 920 includes a first (or third) resonance peak 921 and a second (or fourth) resonance peak 922 . For the sensing device 500, the frequency corresponding to the first resonance peak 921 is the first resonance frequency, the second resonance peak 922 is formed by the action of the first resonance system 530, and the corresponding frequency is the second resonance frequency; for the sensing device 700, the frequency corresponding to the third resonance peak 921 is the third resonance frequency, the fourth resonance peak 922 is formed by the action of the second resonance system 740, and the frequency corresponding to the fourth resonance peak 922 is the fourth resonance frequency.

It should be noted that the second (or fourth) resonance peak 922 shown in the figure is on the left side of the first (or third) resonance peak 921, that is, the frequency corresponding to the second (or fourth) resonance peak 922 is smaller than the first (or fourth) resonance peak 922. (or the third) frequency corresponding to the resonant peak. In some embodiments, by changing the mechanical parameters in the transducer unit or the first (or second) resonance system, the frequency corresponding to the second (or fourth) resonance peak 922 may be greater than the first (or third) resonance The frequency corresponding to the peak 921 , that is, the second (or fourth) resonance peak 922 is on the right side of the first (or third) resonance peak 921 . For example, for a liquid-filled sensing device 500, the second (or fourth) resonant peak 922 may be to the left or right of the first (or third) resonant peak 921, and its position may be similar to that of the liquid-filled Properties (eg, density, kinematic viscosity, volume, etc.) are relevant. For example, if the density of the liquid becomes smaller or the kinematic viscosity becomes larger, its resonance peaks are shifted towards higher frequencies.

In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 100 Hz-12000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 100 Hz-10000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 500Hz-10000Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 1000 Hz-7000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 1500Hz-5000Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 2000 Hz-5000 Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 2000Hz-4000Hz. In some embodiments, the frequency corresponding to the resonance peak 911 is in the range of 3000 Hz-4000 Hz.

In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 100 Hz-12000 Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 500Hz-10000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 1000Hz-10000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 1500Hz-7000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 1500Hz-5000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 2000Hz-5000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 2000Hz-4000Hz. In some embodiments, the frequency corresponding to the first (or third) resonance peak 921 is in the range of 3000Hz-4000Hz.

In some embodiments, the resonant frequency (the first resonant frequency or the third resonant frequency) corresponding to the first (or third) resonant peak 921 is different from the resonant frequency corresponding to the resonant peak 911 . For example, for the sensing device 500 in which the housing cavity 110 is filled with liquid, the liquid is used as the first resonance system 530. Since the liquid is not easily compressible, the stiffness of the system itself increases, and the first resonance peak 921 corresponds to the first resonance peak 921. The frequency is larger than the resonance frequency corresponding to the resonance peak 911 , that is, the first resonance peak 921 is shifted to the right relative to the resonance peak 911 .

In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 50 Hz-12000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 50Hz-10000Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonant peak 922 is in the range of 50Hz-6000Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 100 Hz-5000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 500Hz-5000Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1000 Hz-5000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1000 Hz-3000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1000 Hz-2000 Hz. In some embodiments, the frequency corresponding to the second (or fourth) resonance peak 922 is in the range of 1500Hz-2000Hz.

In some embodiments, the fourth resonant frequency is lower than the second resonant frequency. For the sensing device 500 filled with liquid in the accommodating cavity of the housing 510, the liquid is used as the first resonance system 530. Relatively speaking, in the sensing device 700 containing liquid and air bubbles in the accommodating cavity of the housing 710, the liquid and air bubbles As the second resonant system 740, the combined overall stiffness is lower than that of the liquid, so the fourth resonant frequency is lower than the second resonant frequency.

In some embodiments, one or more mechanical parameters (eg, the type of filling liquid, the size of bubbles, etc.) in the first (or second) resonant system can be adjusted to make the frequency response The two

resonance peaks

921 and 922 on the curve 920 are relatively flat, thereby improving the output quality of the

sensing device

500 or 700 . In some embodiments, the difference in sensitivity between the trough between

resonant peaks

921 and 922 and the peak of the higher peak of

resonant peaks

921 and 922 is not higher than 30 dBV, and the ratio of the difference in sensitivity to the peak value of the higher peak is not higher than 30 dBV. more than 0.2. In some embodiments, the difference in sensitivity between the trough between

resonant peaks

921 and 922 and the peak of the higher peak of

resonant peaks

921 and 922 is not higher than 20 dBV, and the ratio of the difference in sensitivity to the peak value of the higher peak is not higher than 20 dBV. more than 0.15. In some embodiments, the difference in sensitivity between the trough between

resonant peaks

921 and 922 and the peak of the higher peak of resonant peaks 921 and 322 is not higher than 15 dBV, and the ratio of the difference in sensitivity to the peak value of the higher peak is not higher than 15 dBV. more than 0.12. In some embodiments, the trough between

resonant peaks

921 and 922 has a sensitivity difference of no more than 10 dBV from the peak of the higher peak of resonant peaks 921 and 322, and the ratio of the sensitivity difference to the peak value of the higher peak is not more than 10 dBV. more than 0.1. In some embodiments, the trough between the

resonant peaks

921 and 922 has a sensitivity difference of not more than 8 dBV from the peak of the higher peak of the resonant peaks 921 and 322, and the ratio of the sensitivity difference to the peak value of the higher peak is not more than 8 dBV. more than 0.08. In some embodiments, the difference in sensitivity between the trough between

resonant peaks

921 and 922 and the peak of the higher peak of

resonant peaks

921 and 922 is not more than 5 dBV, and the ratio of the difference in sensitivity to the peak value of the higher peak is not more than 5 dBV. more than 0.05.

Correspondingly, the difference between the resonant frequencies corresponding to the resonant peaks 921 and 922 (the frequency of the resonant peak 921 is represented by f ₀ (which is close to the resonant peak 911 ), the frequency of the resonant peak 922 is represented by f ₁ , and the frequency difference Δf ₁ Indicates that the difference between the resonance frequencies corresponding to the resonance peaks 921 and 922) is within a certain range, so that the frequency response curve between the resonance peaks 921 and 922 can be relatively flat. In some embodiments, the frequency difference Δf ₁ is in the range of 200-3000 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.2-0.7. In some embodiments, the frequency difference Δf ₁ is in the range of 200-2000 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.2-0.65. In some embodiments, the frequency difference Δf ₁ is in the range of 500-2000 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.25-0.65. In some embodiments, the frequency difference Δf ₁ is in the range of 500-1500 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.25-0.6. In some embodiments, the frequency difference Δf ₁ is in the range of 800-1500 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.3-0.6. In some embodiments, the frequency difference Δf ₁ is in the range of 1000-1500 Hz, and the ratio of the frequency difference Δf ₁ to f ₀ is in the range of 0.35-0.6.

As shown in FIG. 9 , compared with the frequency response curve 910 , the frequency response curve 920 shows an improvement in sensitivity (ie, the difference in the frequency response curve 920 ) within the frequency range within the resonant frequency f ₁ corresponding to the second (or fourth) resonant peak 922 . , represented by ΔV1) is higher and more stable. In some embodiments, ΔV1 is in the range of 10dBV-60dBV. In some embodiments, ΔV1 is in the range of 10dBV-50dBV. In some embodiments, ΔV1 is in the range of 15dBV-50dBV. In some embodiments, ΔV1 is in the range of 15dBV-40dBV. In some embodiments, ΔV1 is in the range of 20dBV-40dBV. In some embodiments, ΔV1 is in the range of 25dBV-40dBV. In some embodiments, ΔV1 is in the range of 30dBV-40dBV.

The existence of the first resonance system 530 or the second resonance system 740 will inhibit the resonance peak of the

sensing device

500 or 700 corresponding to the transducer unit, so that the first (or third) resonance peak 921 of the frequency response curve 920 The Q value is relatively low at the place, and the frequency response curve is flatter in the desired frequency band (eg, mid-low frequency), and the difference between the peak value of the highest peak and the valley value of the lowest valley of the overall frequency response curve 920 (also known as the peak-to-valley value) value, represented by ΔV2) within a certain range. In some embodiments, the peak-to-valley value does not exceed 30 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.2. In some embodiments, the peak-to-valley value does not exceed 20 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.15. In some embodiments, the peak-to-valley value does not exceed 10 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.1. In some embodiments, the peak-to-valley value does not exceed 8 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.08. In some embodiments, the peak-to-valley value does not exceed 5 dBV, and the ratio of the peak-to-valley value to the peak value of the highest peak does not exceed 0.05.

For the sensing device 700 , in some embodiments, the frequency corresponding to the fourth resonance peak 922 (ie, the fourth resonance frequency) is a middle-low frequency, and the frequency corresponding to the third resonance peak 921 (ie, the third resonance frequency) is a middle-high frequency. In some embodiments, the difference between the minimum value of the sensitivity of the frequency response curve 920 in the frequency range within the resonant frequency f ₁ and the peak value of the fourth resonant peak is not more than 30 dBV, and the ratio thereof is not more than 0.2. In some embodiments, the difference between the sensitivity minimum value of the frequency response curve 920 in the frequency range within the resonance frequency f ₁ and the peak value of the fourth resonance peak is not more than 20 dBV, and the ratio thereof is not less than 0.15. In some embodiments, the difference between the minimum sensitivity value of the frequency response curve 920 in the frequency range within the resonant frequency f ₁ and the peak value of the fourth resonant peak is not greater than 10 dBV, and the ratio thereof is not greater than 0.1.

In some embodiments, the frequency response of the

sensing device

500 or 700 may be determined by the relevant parameters of the curve 920, such as the peak value of the first (or third) resonant peak 921, the frequency, the second (or fourth) resonant peak 922 Peak value, frequency, Q value, △f ₁ , △V1, △V2, the ratio of △f ₁ to f ₀ , the ratio of the peak-to-valley value to the peak value of the highest peak, the first-order coefficient of the equation determined by fitting the frequency response curve Description of one or more of , second-order coefficients, third-order coefficients, etc. In some embodiments, the frequency response of the

sensing device

500 or 700 may be related to properties of the filled liquid and/or parameters of the transducing unit. Properties of the liquid may include, for example, liquid density, liquid kinematic viscosity, liquid volume, presence of bubbles, bubble volume, bubble location, number of bubbles, and the like. The parameters of the transducing element may include, for example, the mass, size, stiffness, etc. of the transducing element (eg, cantilever beam). In some embodiments, the frequency response of the

sensing device

500 or 700 may also be related to parameters such as the internal structure of the housing (eg, the shape of the accommodating cavity), size, stiffness, and the like.

In some embodiments, in order to obtain the ideal output frequency response (eg, the frequency response curve 920 ) of the

sensing device

500 or 700 , the above-listed parameters ( Also known as frequency response influencing factors, including, for example, the properties of the filled liquid and/or the parameters of the transducer elements) range. In some embodiments, the influence of each factor on the frequency response of the

sensing device

500 or 700 can be determined one by one by controlling variables based on simulation. For example, under the premise that the same liquid is filled, the performance of the sensing device with different accommodating cavity structural features is tested. For another example, the performance of devices with different shell stiffness characteristics is tested under the premise that the same liquid is filled. As another example, in the same housing size, the performance of the sensing device is tested under different conditions of being filled with liquid and filled with liquid and air bubbles. For another example, on the premise that the bubble does not cover the transducer unit (eg piezoelectric transducer), the performance of the sensing device with the characteristics of bubbles of different sizes is tested. For another example, on the premise that the bubble covers the transducer unit (such as a piezoelectric transducer), the performance of the sensing device with the characteristics of bubbles of different sizes is tested.

In some embodiments, some factors are related to the influence of other factors on the frequency response of the

sensing device

500 or 700. Therefore, a parameter pair or parameter group may be determined in the form of a corresponding parameter pair or parameter group to affect the

sensing device

500 or 700. 700 frequency response. For example, when the height of the shell becomes larger, the volume of the accommodating cavity becomes larger, the mass of the shell becomes larger, and the volume of the liquid filled in it becomes larger accordingly. Therefore, the height of the shell, the mass of the shell, and the volume of the liquid ( Or the ratio of any two parameters, or the product of at least two parameters, etc.) is used as a parameter group, and the influence of the parameter group on the performance of the sensing device is tested. As another example, liquid viscosity and density can be used as a parameter pair, and the effect of the parameter pair (or its ratio, product, etc.) on the frequency response of the

sensing device

500 or 700 can be tested.

In some embodiments, the influence of parameter pairs or parameter groups corresponding to each factor or multiple factors on the frequency response of the

sensing device

500 or 700 can be determined by means of phantom testing.

Exemplarily, for the sensing device 500 filled with liquids of different viscosities, the greater the viscosity of the liquid, the greater the system damping, and the smaller the Q value of the frequency response of the sensing device 500 . For the sensing device 700 filled with liquid and air bubbles, within a certain kinematic viscosity range, the greater the kinematic viscosity of the filling liquid, the greater the improvement in sensitivity of the sensing device 700 .

In some embodiments, the kinematic viscosity of the liquid may be 0.1-5000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.1-1000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.3-1000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.5-500 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.5-200 cst. In some embodiments, the kinematic viscosity of the liquid may be 50-200 cst.

Exemplarily, for the sensing device 500 filled with liquid, taking a bone conduction microphone or a single-axis accelerometer as an example, within a certain range, the length of the cantilever beam is shortened, and the overall effective frequency band is expanded.

In some embodiments, the thickness, width and length of the cantilever beam may be 0.5um-3mm, 50um-500mm, 200um-1cm, respectively. In some embodiments, the thickness, width and length of the cantilever beam may be 0.5um-1mm, 50um-100mm, 200um-200mm, respectively. In some embodiments, the thickness, width and length of the cantilever beam may be 1 um-100 um, 100 um-10 mm, 400 um-20 mm, respectively. In some embodiments, the thickness, width and length of the cantilever beam may be 2um-20um, 200um-2mm, 800um-4mm, respectively. In some embodiments, the thickness, width and length of the cantilever beam may be 2um-5um, 200um-500um, 800um-1000um, respectively.

Exemplarily, for the sensing device 500 filled with liquid, by increasing the size of the accommodating cavity, the sensitivity of the sensing device at the intermediate frequency can be improved, and the effect of the liquid on the frequency response of the sensing device at the intermediate frequency can be reduced, so that the frequency response curve is reduced. flatter.

Exemplarily, for the sensing device 500 filled with liquid and having different accommodating cavity heights, within a certain range, the higher the accommodating cavity height is, the higher the mid-low frequency output sensitivity of the sensing device 500 is.

In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 1-30 mm, 1-30 mm, and 0.5-30 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 2-30mm, 2-30mm, and 1-30mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 5-10 mm, 5-10 mm, and 1-10 mm. In some embodiments, the length, width, and height of the accommodating cavity of the sensing device are 8-10 mm, 5-10 mm, and 1-5 mm, respectively. Optionally, the accommodating cavity of the sensing device has a larger size. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-200mm, 10-100mm, and 10-100mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-100mm, 10-50mm, and 10-50mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-50mm, 10-30mm, and 10-30mm.

Exemplarily, compared with the sensing device 500 filled with liquid and the sensing device 700 filled with liquid, since the gas is easily compressible and has low rigidity, while the liquid is not easily compressible, over-rigidity and over-damping may occur. The overall output gain is higher. For example, in some embodiments, the sensing device 500 may have a second resonance peak that "disappears" due to over-damping, thereby affecting the sensitivity of the sensing device 500 at mid-low frequencies.

Illustratively, for a liquid and bubble filled sensing device 700, when the bubble does not cover the transducing element (eg, piezoelectric transducer), the sensitivity of the sensing device 700 increases as the volume of the bubble increases.

In some embodiments, the ratio of the volume of the bubbles to the volume of the liquid may be 5%-90%. In some embodiments, the ratio of the volume of the air bubbles to the volume of the liquid may be 10%-80%. In some embodiments, the ratio of the volume of the bubbles to the volume of the liquid may be 20%-60%. In some embodiments, the ratio of the volume of the bubbles to the volume of the liquid may be 30%-50%.

In some embodiments, the bubbles may be located at various locations within the sensing device 700 . For example, air bubbles can be located inside the liquid. As another example, air bubbles may be located between the liquid and the housing. In some embodiments, the transducer unit 720 in the accommodating cavity may partition the accommodating cavity to form a front cavity and a rear cavity on opposite sides of the vibration pickup structure. In this specification, the back cavity refers to the closed or semi-closed space formed by the base body of the transducer unit and the vibration pickup structure (eg, cantilever beam). For example, taking a bone conduction microphone as an example, the accommodating cavity can be divided into a front cavity and a rear cavity by taking the plane where the cantilever beam is located as the dividing plane. For the sensing device 700 filled with liquid and air bubbles, when the air bubble is located in the front cavity of the sensing device and is not in contact with the transducer unit (eg, vibration pickup structure), the sensitivity gradually increases with the increase of the air bubble.

In some embodiments, in the sensing device 700 filled with liquid and air bubbles, when bubbles of a certain size are set in both the front cavity and the rear cavity, the low frequency part can have a larger gain, and the intermediate frequency has a greater effect on the resonance peak of the sensing device 700. The Q value is effectively suppressed, but the sensitivity of other regions other than the resonance peak region of the corresponding sensing device 700 is not suppressed, so that the frequency response of the sensing device 700 is relatively flat in the range of low frequency to medium frequency.

In some embodiments, the ratio of the volume of air bubbles to the volume of liquid in both the front and rear chambers may be 5%-95%. In some embodiments, the ratio of the volume of the air bubbles to the liquid volume in both the front and rear chambers may be 10%-80%. In some embodiments, the ratio of the volume of the air bubbles to the liquid volume in both the front and rear chambers may be 20%-60%. In some embodiments, the ratio of the volume of the air bubbles in the front chamber and the rear chamber to the liquid volume may be 30%-50%.

It should be noted that the above description of the frequency response curve of the

sensing device

500 or 700 is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. It can be understood that for those skilled in the art, after understanding the principle of the system, it is possible to arbitrarily adjust its structure and composition without departing from the principle. Such deformations are all within the protection scope of the present application.

10 is an exemplary frequency response curve of a

sensing device

500 or 700 according to some embodiments of the present specification.

As shown in FIG. 10 , the dotted line 1010 represents the frequency response curve of the sensing device without the equivalent resonance system, and the solid line 1020 represents the frequency response curve of the

sensing device

500 or 700 . The frequency response curve 1010 includes a resonance peak 1011 . In some embodiments, a sensing device without an equivalent resonant system corresponds to a higher resonant frequency that is not in a desired frequency band (eg, 100-5000 Hz, 500-7000 Hz, etc.). In some embodiments, the resonance frequency corresponding to the sensing device without the equivalent resonance system may be in a higher frequency range. For example, in some embodiments, the corresponding resonance frequency of the sensing device without the equivalent resonance system is higher than 7000 Hz. In some embodiments, the corresponding resonance frequency of the sensing device without the equivalent resonance system is higher than 10000 Hz. In some embodiments, the corresponding resonance frequency of the sensing device without the equivalent resonance system is higher than 12000 Hz. Correspondingly, the sensing device without the equivalent resonance system may have higher stiffness at this time, and at the same time, it also brings higher impact strength and reliability to the sensing device.

The frequency response curve 1020 includes a first (or third) resonance peak (not shown in the figure) and a second (or fourth) resonance peak 1021 . In some embodiments, the frequency corresponding to the first (or third) resonant peak is close to or the same as the corresponding resonant frequency in the frequency response curve 1010 . In some embodiments, the frequency response curve 1020 is substantially the same as the frequency response curve 920 in FIG. 9 except that the first (or third) resonance peak is shifted to the right. The frequency corresponding to the second (or fourth) resonance peak 1021 is the same or similar to the frequency range corresponding to the second (or fourth) resonance peak 922 in FIG. 9 .

In some embodiments, within a desired frequency range (eg, within 2000 Hz, within 3000 Hz, within 5000 Hz, etc.), the difference between the maximum and minimum sensitivity values in the frequency response curve 1020 should be kept within a certain range to ensure

Sensing device

500 or 700 frequency response stabilization. In some embodiments, in the desired frequency range, the difference between the maximum and minimum sensitivity values is not higher than 40 dBV, and the ratio of the sensitivity difference value to the maximum value is not more than 0.3. In some embodiments, in the desired frequency range, the difference between the maximum and minimum sensitivity values is not more than 30 dBV, and the ratio of the sensitivity difference value to the maximum value is not more than 0.25. In some embodiments, within the desired frequency range, the difference between the maximum and minimum sensitivity values is not higher than 20 dBV, and the ratio of the sensitivity difference value to the maximum value is not more than 0.15. In some embodiments, in the desired frequency range, the difference between the maximum and minimum sensitivity values is not more than 10 dBV, and the ratio of the sensitivity difference value to the maximum value is not more than 0.1.

In some embodiments, the difference between the resonant frequencies corresponding to the first (or third) resonant peak and the second (or fourth) resonant peak 1021 (the frequency of the first (or third) resonant peak is represented by f ₀ ( close to the resonant peak 1011), the frequency of the second (or fourth) resonant peak 1021 is represented by f1, and the frequency difference _Δf2 represents the difference between the resonant frequencies corresponding to the _two resonant peaks) within a certain range. In some embodiments, the frequency difference Δf ₂ is in the range of 1000-8000 Hz, and the ratio of the frequency difference Δf ₂ to f ₀ is in the range of 0.2-0.8. In some embodiments, the frequency difference Δf ₂ is in the range of 1000-6000 Hz, and the ratio of the frequency difference Δf ₂ to f ₀ is in the range of 0.2-0.65. In some embodiments, the frequency difference Δf ₂ is in the range of 2000-6000 Hz, and the ratio of the frequency difference Δf ₂ to f ₀ is in the range of 0.3-0.65. In some embodiments, the frequency difference Δf ₂ is in the range of 3000-5000 Hz, and the ratio of the frequency difference Δf ₂ to f ₀ is in the range of 0.3-0.5. In some embodiments, the frequency difference Δf ₂ is in the range of 3000-4000 Hz, and the ratio of the frequency difference Δf ₂ to f ₀ is in the range of 0.3-0.4.

Compared with the frequency response curve 1010, the frequency response curve 1020 shows _an improvement in the sensitivity of the frequency response curve 1020 in the frequency range within the resonance frequency f1 corresponding to the second (or fourth) resonance peak 1021 (ie, the difference, represented by ΔV3). ) is higher and more stable. In some embodiments, the boost ΔV3 is in the range of 10dBV-60dBV. In some embodiments, the boost ΔV3 is in the range of 10dBV-50dBV. In some embodiments, the boost ΔV3 is in the range of 15dBV-50dBV. In some embodiments, the boost ΔV3 is in the range of 15dBV-40dBV. In some embodiments, the boost ΔV3 is in the range of 20dBV-40dBV. In some embodiments, the boost ΔV3 is in the range of 25dBV-40dBV. In some embodiments, the boost ΔV3 is in the range of 30dBV-40dBV.

For the sensing device 700 , in some embodiments, the frequency corresponding to the fourth resonance peak 1021 (ie, the fourth resonance frequency) is a middle-low frequency, and the frequency corresponding to the third resonance peak (ie, the third resonance frequency) is a middle-high frequency. In some embodiments, the difference between the minimum sensitivity value of the frequency response curve 1020 in the frequency range within the resonant frequency f ₁ and the peak value of the fourth resonant peak is not greater than 30 dBV, and the ratio thereof is not greater than 0.2. In some embodiments, the difference between the sensitivity minimum value of the frequency response curve 920 in the frequency range within the resonance frequency f ₁ and the peak value of the fourth resonance peak is not more than 20 dBV, and the ratio thereof is not less than 0.15. In some embodiments, the difference between the minimum sensitivity value of the frequency response curve 920 in the frequency range within the resonant frequency f ₁ and the peak value of the fourth resonant peak is not greater than 10 dBV, and the ratio thereof is not greater than 0.1.

In some embodiments, the frequency response of the

sensing device

500 or 700 may be determined by the relevant parameters of the curve 1020, such as the peak value of the primary resonant peak, frequency, the peak value of the secondary resonant peak 1021, frequency, Q value, Δf ₂ , Δ V3, the ratio of Δf ₂ to f ₀ , the ratio of the maximum sensitivity to the minimum sensitivity in the desired frequency range, one of the first-order coefficient, second-order coefficient, third-order coefficient, etc. of the equation determined by fitting the frequency response curve, or Multiple descriptions. In some embodiments, the frequency response of the

sensing device

500 or 700 may be related to properties of the filled liquid and/or parameters of the transducing unit. In some embodiments, in order to obtain the ideal output frequency response (eg, the frequency response curve 1020 ) of the

sensing device

500 or 700 , the above-listed parameters ( Also known as frequency response influencing factors, including the properties of the filled liquid and/or the parameters of the transducer unit), the range is the same as or similar to the method described in FIG. 9 , and will not be repeated here.

11 is a schematic diagram of a sensing device to be filled with liquid according to some embodiments of the present specification.

As shown in FIG. 11 , the sensing device 1100 includes a housing 1110 , a transducer unit 1120 , a processor 1130 and a PCB 1140 . At least one through hole may be provided on the upper surface of the housing 1110 of the sensing device 1100 . The through hole can communicate with the outside world and the accommodating cavity of the sensing device 1100 . Through the at least one through hole, the liquid can be injected into the accommodating cavity of the sensing device 1100 . In some embodiments, the through holes may include liquid injection holes 1111 and exhaust holes 1112 . The liquid can be injected into the accommodating cavity of the sensing device 1100 through the liquid injection hole 1111 . At the same time, through the exhaust hole 1112, the air in the accommodating cavity can be exhausted to ensure that the liquid can completely fill the accommodating cavity, and the transducer unit 1120 and the processor 1130 are immersed in the liquid without air bubbles. Alternatively, the through hole may include only the liquid injection hole 1111 . In a vacuum environment, liquid is injected into the accommodating cavity of the sensing device 1100 through the liquid injection hole 1111, and the accommodating cavity can also be completely filled with the liquid. The transducer unit 1120 and the processor 1130 are immersed in the liquid and do not exist bubble.

In some embodiments, when the sensing device 1100 is filled with liquid without air bubbles, the sensing device 1100 is similar to the sensing device 500 at this time. Due to the viscous effect of the liquid, the damping of the transducer unit 1120 can be increased. The Q value of the resonance peak of the sensing device 1100 (also referred to as the first resonance peak, that is, the peak corresponding to the natural resonance frequency of the transducer unit 1120 ) is reduced. In addition, the liquid is not easily compressible, and over-stiffness and over-damping may occur. At this time, the frequency corresponding to the additional resonance peak (ie, the second resonance peak) formed by adding the liquid is higher, which may be higher than the first resonance peak of the sensing device 1100. Recently, the first resonance peak and the second resonance peak may be at least partially superimposed, so the flatness of the frequency response curve is low.

In some embodiments, the viscosity or density of the liquid filled in the sensing device 1100 is adjusted (eg, by selecting liquids of different densities and viscosities or by adding a specific formulation to adjust the density or viscosity), within a certain range, the sensing device 1100 can be adjusted The Q value of the resonance peak corresponding to the middle transducer unit 1120. For example, within a certain range, the larger the kinematic viscosity of the liquid, the smaller the Q value. In some embodiments, the liquid may have a density of 0.6-2 kg/m ³ . In some embodiments, the liquid may have a density of 0.6-1.4 kg/m ³ . In some embodiments, the liquid may have a density of 0.7-1.1 kg/m ³ . In some embodiments, the liquid may have a density of 0.8-1.0 kg/m ³ . In some embodiments, the liquid may have a density of 0.85-0.95 kg/m ³ . In some embodiments, the liquid may have a density of 0.9-0.95 kg/m ³ . In some embodiments, the liquid may have a density of 0.93-0.95 kg/m ³ .

In some embodiments, the kinematic viscosity of the liquid may be 0.1-5000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.1-1000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.1-1000 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.5-500 cst. In some embodiments, the kinematic viscosity of the liquid may be 0.3-200 cst. In some embodiments, the kinematic viscosity of the liquid may be 50-200 cst.

In some embodiments, the liquid filled in the accommodating cavity may include air bubbles. Bubbles have a certain volume. For example, the ratio of the air bubbles to the volume of the accommodating cavity of the sensing device 1100 may be, for example, any value between 5% and 95%. The number of air bubbles can be 1, 2, 3, 4 or more, which is not specifically limited in the specification of this application.

The bubbles can be in different locations within the sensing device 1100 . Taking the bone conduction microphone as an example, taking the plane where the cantilever beam is located as the dividing plane, the cavity can be divided into a front cavity and a rear cavity. In some embodiments, the air bubble may be within the anterior chamber. Illustratively, the bubble may be located in the anterior chamber away from the cantilever beam, close to the cantilever beam, or attached to the cantilever beam. In some embodiments, the air bubble may be within the back cavity. In other embodiments, air bubbles may be present in both the front and rear chambers.

Air bubbles may be formed by air that is not expelled from the accommodating cavity. For example, when the amount of filling liquid is less than the volume of the accommodating cavity, air bubbles will remain in the accommodating cavity. In some embodiments, air bubbles may be formed by encapsulating the gas by a balloon. For example, the balloon may be a film-like material (eg, polyester film, nylon film, plastic film, composite film, etc.) itself or a closed balloon formed with the housing or components inside the sensing device 1100, which is filled with There is gas. The size and shape of the airbag can be set according to the required volume of the air bubble, the volume and shape of the accommodating cavity, and/or the position of the airbag. In some embodiments, the air bubbles can also be formed by disposing a hydrophobic material on the inner surface of the accommodating cavity or the surface of the components inside the cavity. Air bubbles adhere to the surface of the hydrophobic material. For example, a partial area of the inner surface of the accommodating cavity or a partial surface of its internal components may be provided with a superhydrophobic coating. The superhydrophobic coating can be made of fluorine-containing polymers, such as polytetrafluoroethylene, fluorinated ethylene propylene copolymers, copolymers of ethylene and tetrafluoroethylene, tetrafluoroethylene and perfluoroalkoxy vinyl ether copolymers, etc., Or high molecular melt polymers, such as polyolefin, polycarbonate, polyamide, polyacrylonitrile, polyester, fluorine-free acrylate, molten paraffin, etc., are made by a specific process. The gas in the bubbles can be air, oxygen, nitrogen, inert gas, etc. or any combination thereof. In some embodiments, since the gas has certain elastic properties during the vibration process, the equivalent stiffness of the bubble (or gas) can be changed by changing the gas pressure in the bubble, thereby changing the performance of the second resonance system.

After the sensing device 1100 is filled with liquid and air bubbles, the sensing device 1100 may be similar to the sensing device 700 at this time. Since the bubbles are easy to compress and have low stiffness, the combined stiffness of the liquid and the bubbles is small, and the resonance frequency (also called the fourth resonance peak) corresponding to the resonance peak (also called the fourth resonance peak) of the second resonance system formed by the liquid and the bubbles in the sensing device 1100 The fourth resonant frequency) is relatively low, and the difference between it and the natural resonant frequency (also called the third resonant frequency) of the transducer unit 1120 of the sensing device 1100 is large, which can effectively control the final output performance of the sensing device 1100. Therefore, the overall sensitivity of the sensing device 1100 is greatly improved, the frequency response curve is relatively flat, and the effective bandwidth (satisfying the flat frequency response condition) can cover a wide range. In some embodiments, by adjusting the ratio of the bubble volume to the liquid volume in the sensing device 1100, the position of the fourth resonance peak can be adjusted, so that the third resonance peak and the fourth resonance peak are within a certain frequency band, so that the The frequency response curve of the sensing device 1100 is optimized to be relatively flat.

After the liquid or liquid and air bubbles are filled into the accommodating cavity (eg, the front cavity), the through hole on the upper surface of the housing 1110 will be blocked. In some embodiments, a sealing member may be used to block the through hole. Sealing members may include, for example, plugs, screws, tape, and the like. In some embodiments, the through hole is a circular threaded hole. The sealing member may block the at least one through hole by means of screw connection.

12 is a schematic diagram of an exemplary liquid-filled sensing device shown in accordance with some embodiments of the present specification.

As shown in FIG. 12 , the sensing device 1200 may be a liquid-filled bone conduction microphone, including a housing 1210 , a transducer unit 1220 , a processor 1230 and a PCB substrate 1240 . The accommodating cavity of the housing 1210 is filled with the liquid 1250 . The transducer unit 1220 includes a piezoelectric layer 1221 . The transducer unit 1220 and the processor 1230 are connected by lead wires 1260 . In some embodiments, the structure and internal components of the sensing device 1200 are the same as or similar to those of the sensing device 500 , and details are not described herein again. At least one through hole (not shown in the figure) is provided on the metal casing of the sensing device 1200 . Through the at least one through hole, a liquid 1250 (eg, silicone oil) can be filled into the cavity inside the sensing device 1200 .

In some embodiments, the housing 1210 may be metal, plastic, glass, or the like. In some embodiments, the housing 1210 may be made of a transparent material. Through the transparent casing, it can be observed whether the inner accommodating cavity of the sensing device 1200 is filled with liquid, whether there are air bubbles, and the like.

It should be noted that the above description of the sensing device 1200 is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. It can be understood that those skilled in the art, after understanding the principle of the system, may arbitrarily combine its structures and modules, or form a subsystem to connect with other modules without departing from the principle. For example, the first resonant system 530 or the second resonant system 740 in the form of a liquid or liquid and bubbles can also be incorporated into an audio output device, such as a speaker, to improve the frequency response of the speaker.

13 is a frequency response curve of a sensing device before and after being partially filled with liquid, according to some embodiments of the present application.

As shown in FIG. 13, frequency response curve 1310 represents the frequency response curve of a sensing device (eg, sensing device 1200) filled with a liquid (eg, silicone oil having a kinematic viscosity of 0.65 cst). The frequency response curve 1320 represents the frequency response curve of the sensing device when only a portion of the liquid remains (eg, an oil film is present) after the liquid in the sensing device is withdrawn. In some embodiments, the front chamber of the sensing device is filled with liquid and the rear chamber is partially filled with liquid. The volume of the liquid filled in the back cavity may be 1% to 90% of the volume of the front cavity.

It can be seen that when liquid is filled (e.g., the front chamber is filled with liquid, and the rear chamber is partially filled with liquid), the sensitivity of the sensing device is before low or medium low frequency or high frequency, compared to when only part of the liquid remains (for example, oil film is present) The frequency band (for example, in the frequency band less than 7000Hz, 5000Hz, 3000Hz, 1000Hz or 500Hz) has a relatively large and stable boost. In some embodiments, the sensitivity increase can be as much as 10-50 dBV. In some embodiments, the sensitivity increase can be as much as 10-30 dBV. In some embodiments, the sensitivity increase can be as much as 20-30 dBV.

Although the sensitivity of the sensing device has been greatly improved after filling with liquid, it is in a state of over-damping or over-stiffness, and is over-suppressed near the intermediate frequency, resulting in a rapid drop in the frequency response curve, and the peak at the natural resonant frequency of the transducer unit in the sensing device. suppressed. In order to avoid over-suppression of mid-frequency caused by over-damping, a certain volume of air bubbles can be reserved in the shell. The second resonant system 740 formed by liquid and air bubbles may have less stiffness or damping than the first resonant system 530 filled with liquid (eg, silicone oil), which may alleviate the suppression of mid-frequency.

FIG. 14 is a frequency response curve before and after filling a liquid in a sensing device with a small-sized accommodating cavity according to some embodiments of the present specification.

The sensing device (eg, sensing device 1200 ) is formed after the accommodating cavity of the sensing device (eg, sensing device 1100 ) is filled with liquid. In this embodiment, the accommodating cavity of the sensing device is a small-sized accommodating cavity. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 0.5-10 mm, 0.5-10 mm, and 0.3-10 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 2-10 mm, 2-10 mm, and 0.5-10 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 2-10 mm, 2-10 mm, and 0.5-5 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 3-10 mm, 2-8 mm, and 0.8-5 mm.

Exemplarily, in this embodiment, the accommodating cavity of the sensing device has a smaller size: 3.76mm×2.95mm×0.8-0.85mm. As shown in FIG. 14 , curve 1410 is the frequency response curve of the sensing device with no liquid filled in the cavity. Curve 1420 is a frequency response curve of a sensing device formed by filling the accommodating cavity with liquid (eg, silicone oil with a kinematic viscosity of 0.65 cst). Curve 1430 is the frequency response curve of the sensing device when only the rear chamber is partially filled with liquid. Curve 1440 is the frequency response curve of only the residual oil film on the surface of the transducer unit (eg, cantilever beam) in the sensing device.

Combining curves 1410-1440, it can be seen that for small sized containment chambers, full liquid filling (corresponding to curve 1420) does not result in an increase in the sensitivity of the sensing device. When the small-sized accommodating cavity is filled with liquid, the additional resonant frequency of the liquid is so high that resonance cannot be formed before the natural resonant frequency (first or third resonant frequency) of the transducer unit, and the introduction of the liquid also leads to additional stiffness, The increase in damping suppresses the vibration of the transducer unit, so that the output of the sensing device decreases. When only part of the liquid remains in the back cavity (corresponding to the curve 1430 ), it can be considered that a larger air bubble is introduced into the accommodating cavity of the sensing device. Because the bubbles are easy to compress and have low stiffness, and the combined stiffness of the liquid and the bubbles is small, the resonance frequency (also called the fourth resonance peak) corresponding to the resonance peak (also called the fourth resonance peak) of the second resonance system composed of the liquid and the bubbles in the sensing device Resonant frequency) is lower, and the difference between it and the natural resonant frequency (also called the third resonant frequency) of the transducer unit of the sensing device is larger, so the sensitivity of the sensing device in a wider frequency range is greatly improved .

15 is a frequency response curve of a sensor device with a large-sized accommodating cavity that is not filled with liquid and partially filled with liquid or an oil film exists in the accommodating cavity according to some embodiments of the present specification.

The sensing device (eg, sensing device 1200 ) is formed after the accommodating cavity of the sensing device (eg, sensing device 1100 ) is filled with liquid. In this embodiment, the accommodating cavity of the sensing device is a large-sized accommodating cavity. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 1-30 mm, 1-30 mm, and 0.5-30 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 2-30 mm, 2-30 mm, and 1-30 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 5-10 mm, 5-10 mm, and 1-10 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 8-10 mm, 5-10 mm, and 1-5 mm. Optionally, the accommodating cavity of the sensing device has a larger size. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-200mm, 10-100mm, and 10-100mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-100 mm, 10-50 mm, and 10-50 mm. In some embodiments, the length, width and height of the accommodating cavity of the sensing device are respectively 10-50 mm, 10-30 mm, and 10-30 mm. Exemplarily, in this embodiment, the accommodating cavity of the sensing device has a larger size: 10mm×7mm×1-4mm.

As mentioned above, a sensing device filled with silicone oil in a small-sized accommodating cavity may be in a state of over-damping or over-stiffness, with over-suppressed intermediate frequencies, a rapid drop in the frequency response curve, and the corresponding resonance frequency of the sensing device not filled with liquid. Resonant peaks are completely suppressed. By increasing the size of the accommodating cavity, the output of the sensing device at the intermediate frequency can be improved, the suppression effect of the liquid on the frequency response of the sensing device at the intermediate frequency can be reduced, and the frequency response curve of the sensing device can be flatter.

As shown in FIG. 15 ,

curves

1510 and 1520 respectively represent the frequency response curves of unfilled liquid and partially filled liquid (eg, silicone oil with a kinematic viscosity of 0.65cst) in the large-sized container cavity or the presence of oil film in the container cavity.

It can be seen that when a liquid is partially filled or an oil film exists in the accommodating cavity (corresponding to the curve 1520 ), the frequency response sensitivity of the sensing device is improved to a certain extent compared to the unfilled liquid (corresponding to the curve 1510 ). In some embodiments, the boost is 10-40 dBV. In some embodiments, the boost is 10-30 dBV. In some embodiments, the boost is 10-20 dBV. In some embodiments, the boost is around 15dBV.

16 is a schematic diagram of a sensing device filled with liquid and air bubbles according to some embodiments of the present specification.

Since the inside of the bubble is gas (such as air), its stiffness, mass, and damping are quite different from that of the liquid. Therefore, by controlling the size and position of the introduced bubble, the sensing device (such as the sensing device 1200) can be controlled. The second resonance system 740 (that is, the additional spring-mass-damping system) is adjusted to effectively control the final output performance of the sensing device, so that the frequency response is relatively flat (for example, the peak-to-valley fluctuation is less than 5dBV, 10dBV, 15dBV, etc.), The effective bandwidth (satisfying the flat frequency response condition) covers a certain range (for example, 20Hz-8K Hz), and the overall sensitivity is improved by a certain amount (for example, 10-50dBV).

In this embodiment, the accommodating cavity of the sensing device is a large-sized accommodating cavity. In some embodiments, the size of the accommodating cavity may be 10mm×7mm×1-4mm. Exemplarily, the size of the accommodating cavity of the sensing device is 10mm×7mm×1mm.

In some embodiments, the bubbles may have different sizes, and the positions of the bubbles in the receiving cavity of the sensing device may also be different. As shown in FIG. 16 , the air bubbles can be small air bubbles (for example, the volume ratio of air bubbles to the accommodating cavity is 10% or less), medium or large air bubbles (for example, the volume ratio of air bubbles to the accommodating cavity is 10% to 90%), etc. . The location of the bubble may be the front cavity of the accommodating cavity of the sensing device (away from the cantilever beam, close to or attached to the cantilever beam, etc.), the rear cavity, or both the front cavity and the rear cavity. For more details on the different positions of the bubbles, reference can be made to descriptions elsewhere in this specification, such as Figures 18A-18D and their descriptions.

Just as an example, as shown in FIG. 16 , after the sensing device 1610 is filled with liquid in the accommodating cavity, there is a small bubble in the corner, and the volume of the bubble is about 2%-10% of the liquid volume. Cantilever beam) without any air bubbles. After the sensing device 1620 is filled with liquid in the accommodating cavity, the bubble volume is about 10%-20% of the liquid volume and does not cover the area of the transducer unit. At this time, the transducer unit is completely infiltrated with silicone oil. The sensing device 1630 indicates that after filling the liquid, the volume of the bubbles is about 20%-50% of the liquid volume, and does not cover the area of the transducer unit. At this time, the transducer unit is completely infiltrated by silicone oil. After the sensing device 1640 is filled with liquid in the accommodating cavity, the volume of the bubbles is about 50%-90% of the liquid volume, covering the area of the transducer unit. At this time, the transducer unit is not completely infiltrated by the silicone oil.

FIG. 17 is a frequency response curve of a sensing device containing bubbles of different sizes in the liquid filled in the accommodating cavity according to some embodiments of the present specification.

In this embodiment, the accommodating cavity of the sensing device (eg, the sensing device 1200 ) is a large-sized accommodating cavity. In some embodiments, the size of the accommodating cavity may be 10mm×7mm×1-4mm. Exemplarily, the size of the accommodating cavity of the sensing device is 10 mm×7 mm×1 mm.

As shown in FIG. 17, curve 1710 represents a frequency response curve for a sensing device (eg, sensing device 1100) that is not filled with silicone oil. Curve 1720 represents the frequency response curve of a sensing device containing the small air bubbles shown in FIG. 16 in the filling liquid. Curve 1730 represents the frequency response curve of a sensing device containing small and medium air bubbles as shown in FIG. 16 in the filling liquid. Curve 1740 represents the frequency response curve of a sensing device containing the medium-sized bubbles shown in FIG. 16 in the filling liquid.

Combining the curves 1710-1740, it can be seen that when the bubble does not cover the transducer element (eg, piezoelectric transducer), as the volume of the bubble increases, the sensitivity of the sensing device increases. For example, compared with the sensing device containing small and medium air bubbles (corresponding to curve 1730 ), the low frequency or the low frequency or the frequency band before the high frequency (for example, less than 7000Hz, 5000Hz, 3000Hz, 1000Hz) or 500Hz frequency band) the sensitivity increase is about 5-30dBV. In some embodiments, there is a low frequency roll-off phenomenon in lower frequency bands (eg, in frequency bands below 5000 Hz, below 3000 Hz, 500 Hz or 200 Hz). Compared with the sensing device containing medium-sized bubbles (corresponding to curve 1740 ), the sensor device containing medium-sized bubbles (corresponding to curve 1730 ), the low frequency or the low frequency or the frequency band before the high frequency (for example, less than 7000Hz, 5000Hz, 3000Hz, 1000Hz or 500Hz) In the frequency band) the sensitivity increase is about 5-30dBV.

18A-18D are schematic diagrams of sensing devices for different positions of air bubbles in the filling liquid according to some embodiments of the present specification.

As shown in FIG. 18A , taking the sensing device as the bone conduction microphone 1810 as an example, the transducer unit 1812 may include a cantilever beam. Taking the plane where the transducer unit 1812 is located as the dividing plane, the accommodating cavity of the bone conduction microphone 1810 can be divided into a front cavity 1813 and a rear cavity 1814 . In some embodiments, the space formed by the plane where the base body 1811 and the transducing unit 1812 are located may form the back cavity 1814 . In some embodiments, the space formed by the plane where the base body 1811 and the transducer unit 1812 are located and the part of the housing of the sensing device 1810 may form a back cavity 1814 . The front cavity 1813 may be a space other than the rear cavity 1814 in the accommodating cavity of the bone conduction microphone 1810 .

Front chamber 1813 and rear chamber 1814 in Figure 18A are filled with liquid 1815. The air bubble 1816 is located in the front cavity 1813 and away from the transducer unit 1812 . The air bubbles 1816 may be located in the middle or at the corners of the front cavity 1813 . The bubbles 1816 may be small bubbles (eg, 10% or less of the volume of the bubble to the front cavity), medium or large bubbles (eg, 10% to 90% of the volume of the bubble to the front cavity), and the like.

The structure of the bone conduction microphone 1820 in FIG. 18B is similar to that in FIG. 18A. The base body 1821 and the transducer unit 1822 form a back cavity 1824 . The space other than the rear cavity 1824 in the accommodating cavity of the bone conduction microphone 1820 is the front cavity 1823 . Both the front cavity 1823 and the rear cavity 1824 are filled with liquid 1825. The air bubble 1826 is located in the front cavity 1823 and is attached to or close to the transducer unit 1822 . The air bubbles 1826 may be small air bubbles (eg, 10% or less by volume of air bubbles to the front chamber), medium or large air bubbles (eg, 10% to 90% by volume of air bubbles to the front chamber), and the like.

The structure of the bone conduction microphone 1830 in FIG. 18C is similar to that in FIG. 18A or FIG. 18B . The base body 1831 and the transducer unit 1832 form a back cavity 1834 . The space other than the rear cavity 1834 in the accommodating cavity of the bone conduction microphone 1830 is the front cavity 1833 . Both the front cavity 1833 and the rear cavity 1834 are filled with liquid 1835. Air bubble 1836 is located in back cavity 1834. The air bubbles 1836 may be located in the middle or in the corners of the back cavity 1834 . The bubbles 1836 may be small bubbles (eg, 10% or less by volume of bubble to back cavity), medium or large (eg, 10% to 90% by volume of bubble to back cavity), and the like.

The structure of the bone conduction microphone 1840 in FIG. 18D is similar to that of FIG. 18A , FIG. 18B or FIG. 18C . The base body 1841 and the transducer unit 1842 form a back cavity. At this time, in the accommodating cavity of the bone conduction microphone 1840, only the liquid 1843 (eg, oil film) is attached to the transducer unit 1842. At this time, it can be seen that the air bubbles in the accommodating cavity of the bone conduction microphone 1840 are relatively large (for example, the air bubble to cavity volume ratio exceeds 90% air bubbles), and the filling liquid is very small.

It should be noted that the above description of the sensing device is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. It can be understood that for those skilled in the art, after understanding the principle of the system, it is possible to arbitrarily adjust its structure and composition without departing from the principle. Such deformations are all within the protection scope of the present application. For example, the transducer unit in FIGS. 18A to 18D may also include a diaphragm (the piezoelectric film 32211A shown in FIG. 32A ). The plane on which the diaphragm is located can divide the accommodating cavity into a front cavity and a rear cavity. For another example, the transducer unit in FIGS. 18A to 18D may also include a cantilever beam and a diaphragm (the piezoelectric beam 35211 and the second membrane structure 35213 as shown in FIG. 35B ).

FIG. 19 is a frequency response curve of air bubbles in the filling liquid at different positions in the accommodating cavity of the sensing device according to some embodiments of the present specification.

When the liquid filled in the accommodating cavity of the sensing device contains bubbles of different sizes, corresponding to different spring (Km3, Km4)-mass (Mm4)-damping (Rm3, Rm4) systems, the output performance is also different.

As shown in FIG. 19, curve 1910 represents the frequency response curve of a sensing device (eg, sensing device 1100) containing no liquid in the cavity. Curve 1920 represents the frequency response curve of a sensing device with a liquid (eg, silicone oil) in the front chamber and larger air bubbles with the air bubbles away from the transducing element and a liquid in the back chamber. Curve 1930 represents the frequency response of a sensing device with air in the front cavity and liquid in the back cavity. Curve 1940 represents the frequency response of a sensing device with both the front and back chambers filled with liquid and the back chamber with air bubbles. Curve 1950 represents the frequency response curve of a sensing device with only the transducer element attached to the liquid film.

Combining the curves 1910-1950, it can be seen that when air bubbles are introduced, no matter whether the air bubbles are located in the front cavity, the back cavity, and whether they are in contact with the transducer unit, they can be in the low-frequency or mid-low frequency or mid-high frequency band (for example, less than 7000Hz, 5000Hz, 3000Hz, 1000Hz or 500Hz frequency band) to improve the sensitivity of the sensing device to a certain extent (for example, 10-60dBV, 10-40dBV, 15-40dBV, etc.). The size of the lift is also related to the size and/or location of the bubbles. For example, combining

curves

1920 and 1930, it can be seen that when the bubble is in the front chamber and not in contact with the transducer, the sensitivity increases gradually as the bubble increases.

In addition, in addition to the gain of the sensitivity of the sensing device at low frequency, medium frequency, and high frequency, different combinations of bubbles and liquid have different effects on higher frequency bands. For example, when the back cavity has air bubbles, a smaller effect of higher frequency band suppression can be obtained.

Figure 20 is a frequency response curve before and after filling the sensing device with liquid according to some embodiments of the present specification.

As shown in FIG. 20,

curves

2010 and 2020 are the frequency response curves of a sensing device (eg, sensing device 1100) not filled with liquid and a sensing device filled with liquid with bubbles in the back cavity, respectively.

Combining the

curves

2010 and 2020, it can be known that the sensing device filled with liquid has a resonance peak in the frequency band of 2000-20000 Hz. In contrast, fill liquid and introduce air bubbles in the back chamber (eg, small air bubbles (eg, 10% or less by volume of air bubbles to back chamber), medium or large air bubbles (eg, 10% to 90% by volume of air bubbles to back chamber). %), etc.), the gain of the low frequency or mid-low frequency or the frequency band before the mid-high frequency (for example, in the frequency band less than 7000Hz, 5000Hz, 3000Hz, 1000Hz or 500Hz, etc.) is about 10-40dBV. In some embodiments, the low-band gain is 20-25 dBV. The spring (K m3, 4 )-mass (M _m4) _-damping (R _m3 , 4 ) system composed of air bubbles and liquid forms resonance in the low frequency band, which makes the gain of the sensing device increase greatly in this section. In addition, due to the additional damping and stiffness of the spring (K _m3,4)-mass (M _m4 )-damping (R _m3,4 ) system, the vibration of the sensing device is suppressed, and the corresponding resonance frequency of the sensing device (this The Q value of the resonant peak (eg, the first or third resonant peak) is significantly reduced. In addition, by adjusting the combination of bubble and liquid, the additional spring (K _m3,4 )-mass (M _m4 )-damping (R _m3,4) characteristics of the device can be tuned such that the resonant frequency of the sensing device (eg, the first one or the third resonant frequency) is shifted forward or backward.

In some embodiments, air bubbles of a certain size are arranged in both the front cavity and the rear cavity, so that the low frequency part has a larger gain, and the intermediate frequency can affect the resonance peak (the first or third resonance peak) of the transducer unit in the sensing device. ) is suppressed without suppressing the sensitivity of other regions outside the resonance peak region.

21 is a schematic diagram of an exemplary droplet-containing sensing device shown in accordance with some embodiments of the present specification.

As shown in FIG. 21 , taking a bone conduction microphone as an example, the structure of the sensing device 2100 is similar to the structure of the bone conduction microphones 1810 - 1830 in FIGS. 18A-18C . The sensing device 2100 includes a housing 2110 , a transducer unit 2120 , a droplet 2130 , and a substrate 2140 . Wherein, the accommodating cavity of the housing 2110 is provided with droplets 2130 . The base body 2140 and the transducer unit 2120 constitute the back cavity 2111 . The space other than the rear cavity 2111 in the accommodating cavity in the housing 2110 of the sensing device 2100 is the front cavity 2112 . The droplet 2130 can be located anywhere on the surface of the transducer unit 2120 , so that at least a part of the transducer unit 2120 is connected to the housing 2110 through the droplet 2130 . Droplet 2130 may be equivalent to a spring-mass-damper system (eg, first resonant system 530 or second resonant system 740). The droplet 2130 can adjust the vibration characteristics of the transducer unit 2120 so that its original resonance frequency (eg, the first or third resonance frequency) is changed, while the Q value is in an appropriate range, and due to the presence of newly added resonance peaks (eg, The second or fourth resonance peak), so that the sensing device 2100 has higher sensitivity.

Illustratively, droplets 2130 are present in the anterior chamber 2112. The droplet 2130 is between the transducer unit 2120 and the casing 2110, and its upper and lower parts are connected with the transducer unit 2120 and the casing 2110, respectively. In some embodiments, the volume size of droplet 2130 may be 1% to 80% of the volume of the anterior chamber. In some embodiments, the volume size of droplet 2130 may be 5% to 50% of the volume of the anterior chamber. In some embodiments, the volume size of droplet 2130 may be 10% to 40% of the volume of the anterior chamber. In some embodiments, the volume size of droplet 2130 may be 20% to 30% of the volume of the anterior chamber. Optionally, the droplet 2130 may also be within the rear chamber 2111. In some embodiments, the volume size of the droplet 2130 may be 5% to 80% of the volume of the back cavity. In some embodiments, the volume size of the droplet 2130 may be 5% to 50% of the volume of the back cavity. In some embodiments, the volume size of the droplet 2130 may be 10% to 40% of the volume of the back cavity. In some embodiments, the volume size of the droplet 2130 may be 20%-30% of the volume of the back cavity.

The droplet 2130 can be formed by adding the droplet directly into the containing chamber (eg, the front chamber or the back chamber), or can be formed by other methods, such as film wrapping and the like.

22 is a schematic diagram of an exemplary droplet-containing sensing device shown in accordance with some embodiments of the present specification.

The structure of the sensing device 2200 in FIG. 22 is similar to that in FIG. 21 . As shown in FIG. 22 , the sensing device 2200 includes a housing 2210 , a transducer unit 2220 , a droplet 2230 , and a substrate 2240 . Wherein, the accommodating cavity of the housing 2210 is provided with droplets 2230 . The base body 2240 and the transducer unit 2220 constitute the back cavity 2211 . The space other than the rear cavity 2211 in the accommodating cavity in the housing 2210 of the sensing device 2200 is the front cavity 2212 . The droplet 2230 can be located anywhere on the surface of the transducer unit 2220 , so that at least a part of the transducer unit 2220 is connected to the housing 2210 . In this embodiment, the droplets 2230 include bubbles 2250 . Bubbles in droplets 2230 may be formed by adding gas to the droplets or by other means (eg, film wrapping, etc.). In some embodiments, droplets 2230 form hollow droplets due to the presence of bubbles 2250. In some embodiments, the size and position of the hollow droplet are the same as or similar to those of the droplet 2130, which will not be repeated here. Droplet 2230 and bubble 2250 may be equivalent to a spring-mass-damper system (eg, first resonant system 530 or second resonant system 740). By adding bubbles 2250, the stiffness and/or damping of the introduced spring-mass-damper system can be adjusted over a wider range, resulting in a wider range of newly added resonant frequencies (eg, second or fourth resonant frequencies) and device Q values Make adjustments.

In some embodiments, there is a gap (eg, slit, slot, hole, etc.) between the transducing unit (eg, cantilever beam, membrane, etc.) and the housing of the sensing device. In some embodiments, additional resonant systems of the sensing device (eg, the first resonant system 530 or the second resonant system 740) may be disposed at the gap. The additional resonant system can adjust the original vibration characteristics of the transducer unit 2220, so that the original resonant frequency (eg, the first or third resonant frequency) is changed, while the Q value is in a suitable range, and a new resonant system can also be introduced. There are newly added resonance peaks (eg, the second or fourth resonance peak), so that the sensing device has higher sensitivity.

23A is a schematic diagram of an exemplary sensing device comprising a liquid film shown in accordance with some embodiments of the present specification.

The structure of the sensing device 2300 in FIG. 23A is similar to that of FIGS. 21 and 22 . As shown in FIG. 23A , the sensing device 2300 includes a housing 2310 , a transducer unit 2320 , a liquid film 2330 , and a base 2340 . The base body 2340 and the transducer unit 2320 constitute the rear cavity 2311 . The space other than the rear cavity 2311 in the accommodating cavity in the housing 2310 of the sensing device 2300 is the front cavity 2312 . A gap exists between the transducer unit 2320 and the housing 2310 . The liquid film 2330 may be located in the gap between the transducing unit 2320 and the housing 2310 , so that at least a part of the transducing unit 2320 is connected with the housing 2310 . In some embodiments, the thickness of the liquid film 2330 may be less than, equal to, or greater than the thickness of the transducer unit 2320 .

23B is a schematic diagram of an exemplary sensing device comprising a liquid film shown in accordance with some embodiments of the present specification.

The structure of the sensing device 2350 in Figure 23B is similar to that of Figures 21-22 and 23A. As shown in FIG. 23B , the sensing device 2350 includes a housing 2360 , a transducer unit 2370 , a liquid film 2380 , and a substrate 2390 . The base body 2390 and the transducer unit 2370 constitute the rear cavity 2361 . The space other than the rear cavity 2361 in the accommodating cavity in the housing 2360 of the sensing device 2350 is the front cavity 2362 . There are multiple gaps between the transducer unit 2370 and the housing 2360 . The liquid film 2380 can be located in the gap between the transducing unit 2370 itself and the gap between the transducing unit 2370 and the housing 2360 , so that between each part of the transducing unit 2370 and between at least a part of the transducing unit 2370 and the housing 2360 . connection between. In some embodiments, the thickness of the liquid film 2380 may be less than, equal to, or greater than the thickness of the transducer unit 2370 .

24A is a schematic diagram of an exemplary sensing device comprising a liquid film shown in accordance with some embodiments of the present specification.

The structure of the sensing device 2400 in Fig. 24A is similar to that of Figs. 21-22 and 23A-23B. As shown in FIG. 24A , the sensing device 2400 includes a housing 2410 , a transducer unit 2420 , a liquid film 2430 , and a substrate 2440 . The base body 2440 and the transducer unit 2420 constitute the rear cavity 2411 . The space other than the rear cavity 2411 in the accommodating cavity in the housing 2410 of the sensing device 2400 is the front cavity 2412 . There is a gap between the transducer unit 2420 and the housing 2410 . The liquid film 2430 may be located in the gap between the transducing unit 2420 and the housing 2410 , so that at least a part of the transducing unit 2420 is connected with the housing 2410 . Further, the liquid film 2430 also covers at least part of the surface of the transducer unit 2420 . In this embodiment, the liquid film 2430 also covers the upper surface of the transducer unit 2420 , so as to further improve the performance of the sensing device 2400 .

24B is a schematic diagram of an exemplary sensing device comprising a liquid film shown in accordance with some embodiments of the present specification.

The structure of the sensing device 2450 in Figure 24B is similar to that of Figures 21-22, 23A-23B and 24A. As shown in FIG. 24B , the sensing device 2450 includes a housing 2460 , a transducer unit 2470 , a liquid film 2480 , and a substrate 2490 . The base body 2490 and the transducer unit 2470 constitute the rear cavity 2461 . The space other than the rear cavity 2461 in the accommodating cavity in the housing 2410 of the sensing device 2400 is the front cavity 2462 . There is a gap between the transducer unit 2470 and the housing 2460 . The liquid film 2480 may be located in the gap between the transducing unit 2470 and the housing 2460 , so that at least a part of the transducing unit 2470 is connected with the housing 2460 . Further, the liquid film 2480 also covers at least part of the surface of the transducer unit 2470 . In this embodiment, the liquid film 2480 also covers the upper surface and the lower surface of the transducer unit 2470 , so as to further improve the performance of the sensing device 2450 .

FIG. 25 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. As shown in FIG. 25 , the sensing device 2500 may include a housing 2510 and a transducing unit 2520 , wherein the housing 2510 has a accommodating cavity inside, and the transducing unit 2520 is disposed in the accommodating cavity. The transducer unit 2520 may include a vibration pickup structure 2521 . The vibration pickup structure 2521 divides the accommodating cavity into a front cavity 2530 and a rear cavity 2540 located on opposite sides of the vibration pickup structure 2521 .

The sensing device 2500 may generate deformation and/or displacement based on external signals, such as mechanical signals (eg, pressure, mechanical vibration), acoustic signals (eg, sound waves). The deformation and/or displacement may be further converted into a target signal by the transducer unit 2520 of the sensing device 2500 . The target signal may be an electrical signal, a mechanical signal (eg, mechanical vibration), an acoustic signal (eg, a sound wave), an electrical signal, an optical signal, a thermal signal, and the like. In some embodiments, the sensing device 2500 may be a microphone (eg, a bone conduction microphone), a speaker (eg, a bone conduction speaker), an accelerometer, a pressure sensor, a hydrophone, an energy harvester, a gyroscope, or the like. A bone conduction microphone or bone conduction speaker refers to a microphone or speaker in which sound waves are conducted in a solid body (eg, bone) in a mechanically vibrating manner.

The housing 2510 may be a three-dimensional structure having an accommodating cavity (ie, a hollow portion). In some embodiments, the housing 2510 may be a regular shape such as a cuboid, a sphere, a polygon, a pyramid, or a structure with any irregular shape. In some embodiments, the housing 2510 may utilize metal (eg, stainless steel, copper, etc.), plastic (eg, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and acrylonitrile-butadiene-styrene copolymer (ABS), etc.), composite materials (such as metal matrix composite materials or non-metal matrix composite materials), epoxy resin, phenolic, ceramic, polyimide, glass fiber (eg, FR4-glass fiber), etc., or any combination thereof. In some embodiments, a flexible circuit board (FPC board) can be used as one side of the housing 2510 (eg, the bottom wall of the housing 2510 in FIG. 25 ), and the flexible circuit board 2510 can be used to mount the circuits of the sensing device and replace it. Components such as energy units, and other side walls of the housing 2510 can be made of the materials listed above, which are not further limited herein.

In some embodiments, the transducer unit 2520 may be a piezoelectric transducer. The transducer unit 2520 may include a base body 2522 and a vibration pickup structure 2521 . The vibration pickup structure 2521 may include a cantilever beam (eg, a piezoelectric cantilever beam or a piezoelectric beam), a cantilevered film (eg, a piezoelectric film), and the like supported by the base body 2522 .

In some embodiments, the base body 2522 may be a structure with an open opening, the vibration pickup structure 2521 is located at the open opening of the base body 2522 and covers the opening, and the end of the base body 2522 facing away from the vibration pickup structure 2521 is connected to the housing 2510 is connected to separate the accommodating cavity into a front cavity 2530 and a rear cavity 2540 on opposite sides of the vibration pickup structure 2521 . In some embodiments, the substrate 2522 may employ a semiconductor material. Semiconductor materials may include, but are not limited to, silicon dioxide, silicon nitride, gallium nitride, zinc oxide, silicon carbide, and the like. In some embodiments, the vibration pickup structure 2521 may be physically connected to the base body 2522 . The "connection" described in this specification can be understood as the connection between different parts on the same structure, or after preparing different components or structures, each independent component or structure is welded, riveted, clamped, bolted, glued The connection is fixed by means of adhesive bonding, or during the preparation process, the first part or structure is deposited on the second part or structure by physical deposition (for example, physical vapor deposition) or chemical deposition (for example, chemical vapor deposition) superior. In some embodiments, the base body 2522 may also be a cylindrical structure with two ends passing through. One end of the cylindrical structure is connected to the housing 2510 , and the other end of the cylindrical structure is connected to the vibration pickup structure 2521 . For the specific structure of the vibration pickup structure 2521, reference may be made to FIGS. 30-36B and their descriptions.

In some embodiments, the front cavity 2530 is filled with liquid, and the liquid is in contact with the vibration pickup structure 2521 and the substrate 2522 . The liquid may transmit the vibration of the housing 2510 to the vibration pickup structure 2521 . In some embodiments, the liquid can be selected as a liquid with safety properties (eg, non-flammable and non-explosive) and stable properties (eg, non-volatile, no high temperature deterioration, etc.). For example, the liquid may include oil (eg, silicone oil, glycerin, castor oil, motor oil, lubricating oil, hydraulic oil (eg, aviation hydraulic oil), etc.), water (including pure water, aqueous solutions of other inorganic or organic substances, etc. (eg, brine) )), oil-water emulsion, or other liquids that meet their performance requirements, or a combination of one or more of them.

In some embodiments, the sensing device 2500 may also include one or more conduit structures 2550, each conduit structure 2550 communicating the front chamber 2530 with the exterior of the housing 2510, with at least a portion of the liquid residing in the conduit structures 2550. In some embodiments, the pipe structure 2550 may be an independent structure relative to the casing 2510 , the pipe structure 2550 may be disposed through the side wall of the casing 2510 , or a mounting hole may be provided on the side wall of the casing 2510 , and the pipe structure 2550 is connected to the casing 2510 . The mounting holes on the side walls of the body 2510 are connected. In some embodiments, the duct structure 2550 may be a part of the housing 2510. For example, the sidewall of the housing 2510 extends toward the accommodating cavity to form one or more protrusions having channels, the channels communicating with the accommodating cavity and the accommodating cavity. Outside of housing 2510. In some embodiments, the cross-sectional shape of the duct structure 2550 includes, but is not limited to, regular shapes such as circles, rectangles, ovals, semi-circles, polygons, etc., or any irregular shapes. In some embodiments, the top duct opening of the duct structure 2550 may be flush with the side wall of the housing 2510 , or protrude from the side wall of the housing 2510 .

The casing 2510 of the sensing device 2500 is vibrated by an external force. At this time, the casing 2510 drives the base body 2522 to vibrate. Due to the different properties of the vibration pickup structure 2521 and the casing 2510 or the base body 2522, the vibration pickup structure 2521 and the base body 2522 have different properties. It is impossible to maintain a completely consistent movement, resulting in relative motion, which in turn causes deformation or displacement of the vibration pickup structure 2521 . In some embodiments, the vibration pickup structure 2521 may include at least a piezoelectric layer. When the vibration pickup structure 2521 is deformed, the piezoelectric layer is subjected to deformation stress to generate a potential difference (voltage) to convert vibration signals into electrical signals. The processor 2523 can acquire the electrical signal from the vibration pickup structure 2521 and perform signal processing, where the processor 2523 is similar to the processor shown in FIG. 1 . In some embodiments, each conduit structure 2550 communicates the front cavity 2530 with the exterior of the housing 2510. The outside of the casing 2510 may be an open space (eg, a space communicating with the external environment), or a closed or semi-closed space enclosed by another structure (eg, another part of the casing). In some embodiments, the exterior of the housing 2510 may be filled with a medium other than the liquid in the front cavity 2530 . For example, the outside of the housing 2510 can be filled with gas (eg, air), and at this time, one end of each pipe structure 2550 is located in the liquid in the front cavity 2530 , and the other end communicates with the gas outside the housing 2510 . The liquid and gas connected to each pipe structure 2550 can form a resonant system (the principle is similar to the first resonant system or the second resonant system described above), and the resonant system can act on the exchange through the liquid in the front cavity 2530. energy unit 2520, resulting in additional resonance peaks. Specifically, the vibration of the casing 2510 is transmitted to the pipe structure 2550, and the fluid region corresponding to the pipe structure 2550 (which may include the inner region of the pipe structure 2550 cavity and the vicinity of one end where the pipe structure 2550 protrudes into the liquid, namely a shown in FIG. 25 ) The liquid in the area surrounded by the curve) squeezes the gas corresponding to the pipe structure 2550 (that is, the gas above the pipe structure 2550 shown in FIG. 25 ), thereby generating vibration and acting on the transducer unit 2520, so that the transducer unit 2520 generates The additional resonance peak, the resonance frequency corresponding to the resonance peak is lower than the first resonance frequency generated by the vibration pickup structure 2521 , so that the response of the sensing device 2500 in the lower frequency band is greatly improved.

It should be noted that the above description of the sensing device 2500 is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. For example, the base body may not be limited to a separate structure relative to the housing, and in some embodiments, the base body may also be a part of the housing. As another example, not only the front chamber may be filled with liquid, in some embodiments, both the front chamber and the rear chamber may be filled with liquid. In some embodiments, the liquid can only be filled in the back cavity, and the pipe structure is correspondingly arranged in the back cavity. For the specific structure of the pipe structure disposed in the rear cavity, reference may be made to the description of FIG. 30 .

To enable the sensing device to have multiple resonance peaks and multiple resonance valleys, the sensing device 2500 may include multiple conduit structures, preferably, the conduit structures may have different shapes or sizes.

In some embodiments, the volume of the inner cavity of the pipe structure can be adjusted to adjust the liquid mass in the fluid region corresponding to the pipe structure, so as to adjust the resonance frequency corresponding to the resonance system. In some embodiments, the cavity volumes of the multiple pipe structures may be set to be different, and accordingly, the liquid masses of the fluid regions corresponding to the pipe structures are different, so that the resonance frequencies of the resonance systems corresponding to the multiple pipe structures are different. Factors affecting the volume of the cavity include but are not limited to the cross-sectional area of the pipe structure (the cross-sectional area may be determined by the length, width or radius of the cross-section of the pipe structure) and the height of the pipe structure. The cross-sectional area of the pipe structure refers to the area of the cross-section perpendicular to its extension direction. In some embodiments, the volume of the cavity of the pipeline structure can be adjusted by adjusting the cross-sectional area and/or the height of the pipeline structure, thereby controlling the liquid quality of the cavity inside the pipeline structure. Since the resonance frequencies of the resonance peaks corresponding to the pipe structures with different cavity volumes are different, the multiple resonance systems corresponding to the multiple pipe structures (including the liquid mass in the fluid region and the gas above the liquid surface) can provide the sensing device with additional In addition, among the multiple resonance peaks, since the vibration direction of the liquid in the fluid region of the pipe structure changes, the resonance system corresponding to each pipe structure can provide an additional resonance valley for the sensing device, that is, multiple pipes The structure may additionally provide a plurality of resonance valleys for the sensing device. That is to say, each pipe structure corresponds to an additional set of resonance peaks and resonance valleys of the resonance system. For the specific content of resonance peaks and resonance valleys, reference may be made to FIG. 28 , FIG. 29A and FIG. 29B and their related descriptions.

In some embodiments, a plurality of duct structures may be provided on at least one side wall of the housing. For example, multiple duct structures may be provided on the same side wall of the housing. As another example, multiple duct structures may be provided on different side walls of the housing. In some embodiments, the plurality of duct structures may be regularly or irregularly distributed in rows, columns, rings, etc. on the sidewall of the housing. In some embodiments, the cross-sectional shapes of the plurality of pipe structures may all be the same, may not be the same, or may be different. For example, the cross-sectional shapes of the plurality of duct structures may all be circular. For another example, the cross-sectional shapes of the plurality of duct structures may include any one of a rectangle, a polygon, a circle, a semicircle, an ellipse, or any combination thereof. 26A is a schematic diagram of a plurality of conduit structures shown in accordance with some embodiments of the present specification. As shown in FIG. 26A , the plurality of duct structures 2650A are distributed in a row, and the cross-sectional shapes of the plurality of duct structures are different, which are rectangle, hexagon, ellipse, triangle, and pentagon in sequence. 26B is a schematic diagram of a plurality of conduit structures shown in accordance with some embodiments of the present specification. As shown in FIG. 26B , the plurality of pipe structures 2650B are distributed in a row, and the cross-sectional shapes of the plurality of pipe structures 2650B are all circular.

27 is a mechanically equivalent schematic diagram of a sensing device according to some embodiments of the present specification. 25 and 27 , the arrow a in FIG. 27 represents the acceleration direction of the casing, and the arrow V represents the velocity direction of the vibration pickup structure. The casing 2510 shown in FIG. 25 can be equivalent to the mass Ms. The vibration pickup structure 2520 is equivalent to a spring damping mass system Km-Rm-Mm, where Mm represents the sum of the self mass of the vibration pickup structure 2520 and the additional mass added to the vibration pickup structure 2520 by the liquid. The vibration pickup structure 2520 is connected to the housing 2510, the liquid is equivalent to mass M1, the spring damping effect between the vibration pickup structure 2520 and M1 is equivalent to K1-R1, and the spring damping effect between the housing 2510 and M1 is equivalent to Klb-Rlb. The resonance system corresponding to the pipeline structure 2550 can be equivalent to a spring damped mass system Kl _n -Rl _n -Ml _n , Kl _n -Rl _n is provided by the gas corresponding to the pipeline structure 2550 and the liquid in the fluid region of the pipeline structure 2550, and Ml _n represents the pipeline The structure 2550 corresponds to the liquid mass in the fluid region, the pipe structure 2550 is connected to the housing 2510, and the pipe structure 2550 is in contact with the liquid, and the spring damping effect between the pipe structure 2550 and M1 is equivalent to K1'n-R1'n. The resonance systems corresponding to the plurality of pipeline structures 2550 may be equivalent to a plurality of Kln-Rln-Mln systems connected in parallel. Here n can be any positive integer (

eg

1, 2...). In some embodiments, the sensing device may include duct structure 1, duct structure 2 . . . duct structure n. The pipeline structure 1 can be equivalent to a spring damping mass system Kl ₁ -Rl ₁ -Ml ₁ , and Kl ₁ -Rl ₁ is composed of the gas corresponding to the pipeline structure 1 (that is, the gas located at the outlet of the pipeline structure 1) and the fluid area of the pipeline structure 1. Liquid is supplied, Ml ₁ represents the liquid mass in the fluid region corresponding to the pipeline structure 1, and the spring damping effect between the resonance system corresponding to the pipeline structure 1 and Ml is equivalent to Kl' ₁ -Rl' ₁ . The resonance system corresponding to the pipeline structure 2 can be equivalent to a spring damping mass system Kl ₂ -Rl ₂ -Ml ₂ , Kl ₂ -Rl ₂ is provided by the gas corresponding to the pipeline structure 2 and the liquid in the fluid region of the pipeline structure 2, and Ml ₂ represents the pipeline Structure 2 corresponds to the liquid mass in the fluid region, and the spring damping effect between pipe structure 2 and Ml is equivalent to Kl' ₂ -Rl' ₂ .

The spring damped mass system Km-Rm-Mm and the spring damped mass system Kl _n -Rl _n -Ml _n have different elasticity, damping and mass respectively, so that each spring damped mass system can have different resonance peaks, and the sensing device includes Multiple spring damped mass systems with different resonance peaks allow the frequency response curve of the sensing device to have multiple resonance peaks. 28 is a frequency response curve of a sensing device according to some embodiments of the present specification. In Fig. 28, the abscissa represents the frequency in Hertz Hz, and the ordinate represents the sensitivity, in volts decibels dBV. The curve 281 is the frequency response curve of the sensing device without the liquid and pipeline structure, and the resonance frequency f0 corresponding to the resonance peak 2811 thereof is the first resonance frequency. Curve 282 is a frequency response curve of a sensing device with a liquid and pipe structure, and the equivalent spring damped mass system (eg, Kl _n -Rl _n -Ml _n ) of the resonance system corresponding to the pipe structure resonates at the resonance frequency, so that The curve 282 can be made to have multiple resonance peaks (including resonance peak 2821 ) and multiple resonance valleys (including resonance valley 2822 ). The resonance frequencies corresponding to the multiple resonance peaks are respectively f0 ₁ , f0 ₂ ...... f0 _n , and the resonance frequencies corresponding to the multiple resonance valleys are respectively f0 _-1 , f0 _-2 ...... f0 _-n . Here n corresponds to n of the spring-damped mass system Kl _n -Rl _n -Ml _n . In some embodiments, the relationship between the resonant frequencies corresponding to the multiple resonant peaks here may be similar to that of the first (or third) resonant peak 921 and the second (or fourth) resonant peak 922 in the curve 920 in FIG. 9 . The relationship between the resonant frequencies of , will not be repeated here. Continuing to refer to FIG. 28 , the sensitivity of the sensing device with the liquid and the pipeline structure is greatly improved compared to the sensing device without the liquid and the pipeline structure, and the improvement range may be ΔV4. In some embodiments, ΔV4 may be 10dBV-60dBV. Preferably, ΔV4 may be 20dBV-60dBV. Further preferably, ΔV4 may be 30dBV-50dBV. In some embodiments, by reducing the viscosity of the liquid, the amplitude of the resonance peak provided by the pipeline structure is higher, thereby improving the sensitivity of the sensing device in the frequency range near the resonance frequency corresponding to the resonance peak. In some embodiments, the amplitudes of the multiple resonance peaks provided by the multiple pipe structures are higher, so that the sensing device can maintain a better response in a wider frequency band.

The liquid in the fluid region corresponding to the pipe structure vibrates in the same or opposite direction as the vibration pickup structure, so that the frequency response curve of a sensing device with a resonant system (eg, a spring-mass system Kl _n -Rl _n -Ml _n ) Has a resonance peak (eg, resonance peak 2821 in FIG. 28 ) or a resonance valley (eg, resonance valley 2822 in FIG. 28 ). For the specific principles of generating resonance peaks and resonance valleys, reference may be made to the specific descriptions in FIG. 29A and FIG. 29B . FIG. 29A is a schematic diagram of the vibration direction of the sensing device at the resonance peak according to some embodiments of the present specification. As shown in FIG. 29A , when the sensing device is at the resonance frequency f0 _n corresponding to the resonance peak, the liquid vibration direction in the fluid region of the pipeline structure 2950A is in the same direction as the vibration direction of the vibration pickup structure 2921A, and the liquid vibration displacement is the same as that of the vibration pickup structure 2921A. The vibration displacement of the superimposed, increasing the amount of deformation, so that the sensing device generates a resonance peak at f0 _n . FIG. 29B is a schematic diagram of the vibration direction of the sensing device according to some embodiments of the present specification when it is in a resonance valley. As shown in FIG. 29B , when the sensing device is at the resonance frequency f0 _−n corresponding to the resonance peak, the vibration direction of the liquid in the fluid region of the pipeline structure 2950B is opposite to that of the vibration pickup structure 2921B, and the vibration displacement of the liquid is opposite to that of the vibration pickup structure. The vibration displacement of 2921B is partially offset, reducing the amount of deformation, so that the sensing device produces a resonance valley at f0 _-n .

In some embodiments, by pairing multiple resonant systems (eg, spring-mass system Kl ₁ -Rl ₁ -Ml ₁ , spring-mass system Kl ₂ -Rl ₂ -Ml ₂ , spring-mass system Kl _n -Rl _n in FIG. 27 ) -M1 _n , etc.) in the vibration signal near each resonance peak to perform acousto-electric conversion, can realize the sub-band frequency division of the vibration signal. For example, considering the existence of multiple resonance peaks, a filter is set near the resonance frequency corresponding to each resonance peak, and even a low-order filter can extract sub-band signals of higher quality. In this way, the sensing device provided by the embodiments of this specification can help realize sub-band frequency division processing of full-band signals through its own structure under the premise of low-cost hardware circuits (for example, filter circuits) or software algorithms, avoiding high Cost The hardware circuit design is complex and the software algorithm occupies high computing resources, which brings about the problems of signal distortion and noise introduction.

Just as an example, the method for determining the frequency response curve of the sensing device shown in FIG. 28 may include: providing a measurement voltage to the sensing device in the measurement circuit, and plotting the frequency response curve of the sensing device by a level recorder.

FIG. 30 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. As shown in FIG. 30, the sensing device 3000 may include a housing 3010, a transducing unit 3020 and a pipe structure 3050, wherein the housing 3010 has a accommodating cavity inside, the transducing unit 3020 is arranged in the accommodating cavity, and the vibration pickup structure The accommodating cavity is divided into a front cavity 3030 and a rear cavity 3040 located on opposite sides of the vibration pickup structure. The rear cavity 3040 is filled with liquid, and the liquid contacts the vibration pickup structure 3021. The pipe structure 3050 connects the rear cavity 3040 to the housing 3010 External communication, the liquid is located at least partially in the conduit structure 3050. The casing 3010 , the transducer unit 3020 and the pipe structure 3050 shown in FIG. 25 are similar to the casing 2510 , the transducer unit 2520 and the pipe structure 2050 shown in FIG. 25 , and will not be repeated here.

FIG. 31A is a schematic structural diagram of part A in FIG. 25 . As shown in FIG. 31A , the vibration pickup structure 2521 may include a piezoelectric layer 310A and an electrode layer 320A, and the electrode layer 320A may be located on the upper surface and/or the lower surface of the piezoelectric layer 310A.

In some embodiments, the electrode layer 320A has a first electrode layer 321A and a second electrode layer 322A, and the piezoelectric layer 310 may be located between the first electrode layer 321A and the second electrode layer 322A. In some embodiments, a side of the second electrode layer 320 facing away from the piezoelectric layer 310 is connected to the base body 2522 . When the vibration pickup structure 2521 receives the vibration signal, the vibration pickup structure 2521 is deformed or displaced, the piezoelectric layer 310 can generate a potential difference under the action of the deformation stress based on the piezoelectric effect, and the electrode layers 320 (for example, the first electrode layer 321A and the The second electrode layer 322A) can collect the potential difference and transmit it to the processor 2523, thereby converting the external vibration signal into an electrical signal.

In some embodiments, the material of the piezoelectric layer may include piezoelectric crystal material and piezoelectric ceramic material. Piezoelectric crystal material refers to piezoelectric single crystal. In some embodiments, the piezoelectric crystal material may include crystal, sphalerite, boronite, tourmaline, hematite, GaAs, barium titanate and derivatives thereof, KH ₂ PO ₄ , NaKC ₄ H ₄ O ₆ · 4H ₂ O (roshi salt), etc., or any combination thereof. Piezoelectric ceramic materials refer to piezoelectric polycrystals formed by random collection of fine crystal grains obtained by solid-phase reaction and sintering between powders of different materials. In some embodiments, the piezoelectric ceramic material may include barium titanate (BT), lead zirconate titanate (PZT), lead barium lithium niobate (PBLN), modified lead titanate (PT), aluminum nitride (AIN) ), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the material of the piezoelectric layer may also be a piezoelectric polymer material, such as polyvinylidene fluoride (PVDF) and the like.

In some embodiments, the material of the electrode layer may be a conductive material. Exemplary conductive materials include metals, alloy materials, metal oxide materials, graphene, etc., or any combination thereof. In some embodiments, the metal and alloy materials may include nickel, iron, lead, platinum, titanium, copper, molybdenum, zinc, or any combination thereof. In some embodiments, the alloy material may include copper-zinc alloy, copper-tin alloy, copper-nickel-silicon alloy, copper-chromium alloy, copper-silver alloy, etc., or any combination thereof. In some embodiments, the metal oxide material may include RuO ₂ , MnO ₂ , PbO ₂ , NiO, etc., or any combination thereof.

In some embodiments, in order to support or transmit displacement to the electrode layer 320A and the piezoelectric layer 310A, the vibration pickup structure may further include a substrate layer 330A, which may be located between the second electrode layer 322A and the base body 2522 . In some embodiments, the substrate layer 330A may be a single-layer structure or a multi-layer composite structure made of one or more semiconductor materials. It should be noted that the vibration pickup structure shown in FIG. 31A is only an example, and the vibration pickup structure cannot be limited to the scope of the illustrated embodiment. For example, the vibration pickup structure may also include other structural layers, or have multiple piezoelectric layers. In some embodiments, the vibration pickup structure may further include a first piezoelectric layer and a second piezoelectric layer, and an electrode layer 320 is disposed between the first piezoelectric layer and the second piezoelectric layer.

FIG. 31B is another schematic diagram of the structure of part A in FIG. 25 . As shown in FIG. 31B , the vibration pickup structure 2521 may include a first electrode layer 321B, a first piezoelectric layer 311B, a second electrode layer 322B, a second piezoelectric layer 312B, and a third electrode layer 323B arranged in order from top to bottom , wherein the side of the third electrode layer 323B facing away from the second piezoelectric layer 312B is connected to the base body 2522 .

When the vibration pickup structure 2521 receives the vibration signal, the piezoelectric layers (eg, the first piezoelectric layer 311B, the second piezoelectric layer 312B) are subjected to deformation stress to generate a potential difference (voltage), and the electrode layers (eg, the first electrode layer 321B) , the second electrode layer 322B and the third electrode layer 323B) can collect the potential difference and transmit it to the processor 2522, so as to convert the external vibration signal into an electrical signal.

In some embodiments, the vibration pickup structure may cover the opening of the substrate to prevent liquid in the front chamber from entering the back chamber. In some embodiments, a surface of the vibration pickup structure is connected to the side of the base body away from the bottom wall of the casing and covers the opening of the base body, and a surface of the vibration pickup structure away from the base body is in contact with the liquid. In some embodiments, the vibration pickup structure may be connected to the side wall of the base body through its peripheral side, where the vibration pickup structure is adapted to the shape and size of the opening of the base body. In some embodiments, the shape of the vibration pickup structure may include, but is not limited to, regular shapes such as circles, rectangles, ellipses, semi-circles, polygons, etc., or any irregular shapes. The piezoelectric film and the substrate are exemplarily described below with reference to FIGS. 32A and 32B . FIG. 32A is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification. As shown in FIG. 32A , in some embodiments, the base body 32212A may be a square cylinder structure with two ends penetrating or one end having an opening, the shape of the opening of the base body 32212A may be circular, and the piezoelectric film 32211A may be the same as the shape of the opening Fits the circle. FIG. 32B is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification. As shown in FIG. 32B , in some embodiments, the base body 32212B may be formed into a square cylinder structure with two ends penetrating or one end having an opening. The shape of the opening may be a circle, and the piezoelectric film 32211B may be a square that matches the shape of the opening.

It should be understood that the piezoelectric film may not be adapted to the shape of the opening, for example, the shape of the piezoelectric film may be a square, and the shape of the opening of the substrate may be a triangle.

In some embodiments, the sensing device may include a plurality of piezoelectric beams. In some embodiments, the multiple piezoelectric beams may be multiple identical piezoelectric beams, for example, the length, thickness, material and other factors of the multiple piezoelectric beams are all the same. When the centroids of the multiple piezoelectric beams are located in the same plane, the multiple piezoelectric beams can provide a better acoustic output effect for the sensing device, which means that when the same excitation signal is input, the sensing device can output a larger response. In some embodiments, the multiple piezoelectric beams may be multiple different piezoelectric beams, for example, the length, thickness, material and other factors of the multiple piezoelectric beams and their positions are arbitrarily different. A plurality of different piezoelectric beams can provide different resonance peaks for the sensing device, enhancing the response of the sensing device in any specific frequency band (eg, in the frequency range of 20Hz-1000Hz). For more descriptions of piezoelectric beams, reference can be made to content elsewhere in this specification, eg, Figures 33, 35A, and 35B and their associated descriptions.

FIG. 33 is a schematic diagram of a vibration pickup structure according to some embodiments of the present specification. As shown in FIG. 33 , in some embodiments, the vibration pickup structure 3321 may include a base body 33212 and four piezoelectric beams 33211, each piezoelectric beam 33211 extends toward the center of the opening of the base body 33212, and the four piezoelectric beams The 33211 is symmetrically distributed along the geometric center of the opening, and the four piezoelectric beams 33211 jointly realize the coverage of the opening of the base body 33212. For illustrative purposes only, the opening of the base body in FIG. 33 is a square, each piezoelectric beam 33211 may be an isosceles right triangle with the same size, and the hypotenuse of each piezoelectric beam 33211 is connected to the side wall of the base body 33212 at the opening. After connecting, the right-angled sides of the four piezoelectric beams 33211 are spliced together to form a square with the same shape as the shape of the opening.

In some embodiments, the shapes formed by splicing a plurality of piezoelectric beams include, but are not limited to, regular shapes such as circles, rectangles, ellipses, semi-circles, and polygons, or any irregular shapes. In some embodiments, the shapes of each piezoelectric beam may be the same or different, and the shapes include but are not limited to regular shapes such as sectors, triangles, rectangles, semicircles, polygons, etc., or any irregular shapes. In some embodiments, the vibration pickup structure may include a base body and two piezoelectric beams, and the two piezoelectric beams jointly cover the opening of the base body. In some embodiments, the two piezoelectric beams may be semi-circular shapes of the same size, the arc edge of the piezoelectric beams is connected to the sidewall of the opening of the base body, and the straight edges of the two piezoelectric beams are connected to each other to form a connection with the opening. Mouth-to-mouth round shape. In some embodiments, the vibration pickup structure may include a base body and three piezoelectric beams, and the three piezoelectric beams jointly cover the opening of the base body. In some embodiments, the three piezoelectric beams may be fan-shaped with the same size, the arc edges of the piezoelectric beams are connected to the sidewall of the opening of the base body, and the straight edges of the three piezoelectric beams are connected in pairs to form the opening. Compatible round shape. In some embodiments, the piezoelectric beam 33211 may include an electrode layer and a piezoelectric layer. For the arrangement of the electrode layer and the piezoelectric layer and more details, please refer to FIG. 31A , FIG. 31B and related content. The base body 33212 shown in FIG. 33 is similar to the base body 2522 shown in FIG. 25 and will not be repeated here.

In order to prevent the liquid in the front cavity and/or the back cavity from flowing through the gaps between the piezoelectric beams 33211, in some embodiments, the vibration pickup structure may further include a blocking structure 33213, and the blocking structure 33213 fills or covers one of the piezoelectric beams 33211. gap between. For example, the blocking structure 33213 may be located on the upper surface or the lower surface of the plurality of piezoelectric beams 33211 to cover the gaps between the plurality of piezoelectric beams 33211 . For another example, the blocking structure 33213 may be located at the gap between two adjacent piezoelectric beams 33211 . For another example, a part of the blocking structure 33213 can be filled in the gap between two adjacent piezoelectric beams 33211, and another part can be located on the upper surface or the lower surface of the plurality of piezoelectric beams 33211 to cover the plurality of piezoelectric beams Gap between 33211. Considering that the blocking structure 33213 will hinder the vibration of the piezoelectric beam connected to it, in some embodiments, in order to reduce this effect as much as possible, the material of the blocking structure 33213 may be selected to have a smaller Young's modulus, such as the blocking structure 33213. The style modulus should be less than the Young's modulus of the electrode layer or piezoelectric layer. In some embodiments, the material of the barrier structure 33213 may be a semiconductor material, a non-metallic material or a flexible material. Exemplary non-metallic materials may include plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and acrylonitrile-butadiene-styrene copolymers. (ABS), etc.), composites (eg, non-metal matrix composites), etc., or any combination thereof. Exemplary flexible materials may include rubber, latex, silicone, sponge, etc., or any combination thereof. Regarding the manner in which the blocking structure fills or covers the gaps between the plurality of piezoelectric beams, reference may be made to the related content of FIGS. 34A-34D .

34A is a cross-sectional view of B-B in FIG. 33, shown in accordance with some embodiments of the present specification. As shown in FIG. 34A, the blocking structure 34213A fills the gap between two adjacent piezoelectric beams 34211A. In some embodiments, the perimeter side of the barrier structure 34213A may be connected to the corresponding piezoelectric beam 34211A at the gap. In some embodiments, along the vibration direction of the piezoelectric beam 34211A, the end surface of the blocking structure 34213A may be flush with the surface of the piezoelectric beam 34211A. In some embodiments, along the vibration direction of the piezoelectric beam 34211A, the end surface of the blocking structure 34213A may be convex or concave relative to the surface of the piezoelectric beam 34211A.

FIG. 34B is a cross-sectional view of B-B in FIG. 33 according to some embodiments of the present specification. As shown in FIG. 34B , the blocking structure 34213B covers the gap between two adjacent piezoelectric beams 34211B, and the blocking structure 34213B is located on the side of the piezoelectric beam 34211B away from the base 34212B.

34C is a cross-sectional view of B-B in FIG. 33, shown in accordance with some embodiments of the present specification. As shown in FIG. 34C , the blocking structure 34213C covers the gap between two adjacent piezoelectric beams 34211C, and the blocking structure 34213C is located on the side of the piezoelectric beam 34211C close to the base 34212C.

In order to further improve the filling and sealing of the gap between the piezoelectric beams by the blocking structure, the blocking structure can cover and fill the gap between two adjacent piezoelectric beams. 34D is a cross-sectional view of B-B in FIG. 33, shown in accordance with some embodiments of the present specification. As shown in Figure 34D, the barrier structure 34213D surrounds the gap between the piezoelectric beams 34211D.

In some embodiments, the blocking structure 34213D includes a first structure part 1, a second structure part 2 and a third structure part 3, the first structure part 1 fills the gap between two adjacent piezoelectric beams 34211D, and the first structure part 1 fills the gap between two adjacent piezoelectric beams 34211D. The two-part structure 2 and the third structure part 3 respectively cover the gap between the two adjacent piezoelectric beams 34211D, the second structure part 2 is located on the side of the piezoelectric beam 34211D away from the base 34212D, and the third structure part 3 It is located on the side of the piezoelectric beam 34211D close to the base 34212D. In some embodiments, the peripheral side of the first structure part 1 may be connected with the piezoelectric beam 34211D corresponding to the gap. In some embodiments, along the vibration direction of the piezoelectric beam 34211D, the end surface of the first structural part 1 may be flush with the surface of the piezoelectric beam 34211D. In some embodiments, along the vibration direction of the piezoelectric beam 34211D, the end surface of the first structure part 1 may be recessed relative to the surface of the piezoelectric beam 34211D. In some embodiments, the first structure part 1 , the second structure part 2 and the third structure part 3 of the blocking structure 34213D may be independent structures, or may be integrated (eg, integrally formed).

Optionally, when the gap between the piezoelectric beams is sufficiently small, the surface of the piezoelectric beams will have a sufficient blocking effect on the liquid so that the liquid will not pass through the gap. In some embodiments, the gap between piezoelectric beams may be no greater than 20um. Preferably, the gap between the piezoelectric beams may not be greater than 15um. Further preferably, the gap between the piezoelectric beams may not be greater than 10um.

Fig. 35A is a schematic structural diagram of a sensing device according to some embodiments of the present specification, and Fig. 35B is a structural schematic diagram of a vibration pickup structure according to some embodiments of the present specification. The overall structure of the sensing device 3500 shown in FIG. 35A is substantially the same as that of the sensing device 2500 shown in FIG. 25 , and the main difference is that the vibration pickup structure is different. As shown in FIGS. 35A and 35B , the vibration pickup structure 3521 may include a piezoelectric beam 35211 and a second membrane structure 35213 . The base body 3522 is a structure with an open opening, the piezoelectric beam 35211 is disposed at the opening, and the second membrane structure 35213 covers the opening of the base body 3522 . The casing 3510 and the pipe structure 3550 shown in FIG. 35A are similar to the casing 2510 and the pipe structure 2550 shown in FIG. 25 , and the base body 3522 is similar to the base body 2522 shown in FIG. 25 , and will not be repeated here.

In some embodiments, the piezoelectric beam 35211 can be a cantilever beam structure with a long strip shape. Two ends of the piezoelectric beam 35211 are a fixed end and a free end, respectively. The fixed end can be connected to the side of the base body, and the free end can be suspended. at the opening of the base. In some embodiments, the piezoelectric beam 35211 may include an electrode layer and a piezoelectric layer, both of which are arranged along its long axis direction (the e direction shown in FIG. 35A ) and along its thickness direction ( FIG. 35A ). shown in the f direction) overlap. Regarding the arrangement of the electrode layer and the piezoelectric layer and more contents, please refer to FIG. 31A , FIG. 31B and related contents. In some embodiments, the polarization direction of the piezoelectric beam 35211 is perpendicular to the stress direction. Here, when the piezoelectric beam 35211 receives a vibration signal transmitted by the substrate, the direction of the stress received by the piezoelectric beam 35211 during the vibration process is the direction of its long axis. , the piezoelectric beam 35211 is deformed as a whole, and the polarization direction is perpendicular to its long axis direction. After the piezoelectric layer is subjected to deformation stress, a potential difference (voltage) is generated between the upper and lower surfaces of the piezoelectric layer. The electrode layers on both sides of the piezoelectric layer (for example, the first An electrode layer and a second electrode layer) can collect the potential difference to convert the external vibration signal into an electrical signal. A single piezoelectric beam can be regarded as a signal acquisition unit, which can have unique resonance peaks. In some embodiments, the structural parameters of the piezoelectric beam 35211 (such as the volume, mass, width of the piezoelectric beam and the thickness of the piezoelectric layer and electrode layer, etc.) can be adjusted to adjust the resonance peak of the piezoelectric beam 35211. Resonant frequency.

In order to improve the sensitivity of the sensing device in a wider frequency band, a plurality of piezoelectric beams 35211 can be provided, and the plurality of piezoelectric beams 35211 can vibrate to generate resonance peaks of different frequencies. Each piezoelectric beam 35211 can be used as a separate signal acquisition unit to output sub-electrical signals. In some embodiments, each sub-electrical signal can be directly output to a processor (eg, the processor 2523 shown in FIG. 25 ) in the form of electrical series, parallel, or a combination of series and parallel. In some embodiments, each electrical sub-signal may be individually transmitted to the processor, and the processor performs signal processing on each electrical sub-signal individually (including but not limited to adjusting amplitude, phase, etc.), and then performs corresponding signal fusion. More descriptions of how the sub-electrical signals of the individual piezoelectric beams are processed can be found, for example, in the PCT application entitled "MICROPHONE AND ELECTRONIC DEVICE HAVING THE SAME", application number PCT/CN2020/103201, the content of which is Incorporated herein by reference. In some embodiments, the opening of the base body can be rectangular, the fixed end of the piezoelectric beam 35211 can be connected to any side wall of the opening, the free end of the piezoelectric beam 35211 can be suspended in the opening, and the piezoelectric beam 35211 can be suspended in the opening. The fixed ends of the 35211 are spaced apart on the open side walls. In some embodiments, the fixed ends of the plurality of piezoelectric beams 35211 may be disposed on the same sidewall of the opening. In some embodiments, the plurality of piezoelectric beams 35211 on the same sidewall of the opening are sequentially spaced apart. In some embodiments, the plurality of piezoelectric beams 35211 distributed at intervals on the same sidewall of the opening are on the same plane and approximately parallel. In some embodiments, a plurality of piezoelectric beams 35211 may be disposed on opposite sidewalls of the opening. In some embodiments, the free ends of a plurality of piezoelectric beams 35211 respectively disposed on opposite sidewalls of the opening are distributed at intervals in the opening. In some embodiments, the plurality of piezoelectric beams 35211 disposed on opposite sidewalls of the opening are on the same plane and approximately parallel. In some embodiments, a plurality of piezoelectric beams can be distributed on the four side walls of the opening. For example, the free ends of the piezoelectric beams 35211 distributed on the four side walls of the opening are all facing the opposite open side. wall extension.

In some embodiments, the opening can be annular, the fixed ends of the piezoelectric beams can be distributed on the annular inner wall of the opening at intervals, the fixed ends of the piezoelectric beams can be approximately perpendicular to the annular inner wall, and the fixed ends of the piezoelectric beams 35211 The ends extend toward the center of the opening and are suspended in the opening, so that a plurality of piezoelectric beams are distributed annularly in the same plane. In some embodiments, when the opening may also be a polygonal structure (eg, triangular, pentagonal, hexagonal, etc.), in the same plane, the fixed ends of the plurality of piezoelectric beams may be along at least one side of the opening wall space distribution. In some embodiments, multiple different piezoelectric beams with different resonance frequencies (for example, piezoelectric beams with different structural parameters) can be set, so that the vibration pickup structure can generate multiple resonances for the vibration signal of the housing. Peak frequency response. Since the piezoelectric beam is sensitive to vibration near its resonant frequency, it can be considered that the piezoelectric beam has a frequency-selective characteristic to the vibration signal, that is, the piezoelectric beam will mainly convert the sub-band vibration signal near its resonant frequency in the vibration signal. converted into electrical signals.

In some embodiments, by setting different structural parameters, different piezoelectric beams can have different resonant frequencies, so that sub-bands are formed respectively around each resonant frequency. In some embodiments, by adjusting the structural parameters of the plurality of piezoelectric beams to be different, at least 5 sub-bands can be formed in the vocal frequency range (eg, 20 Hz-16000 Hz). In some embodiments, by adjusting the structural parameters of the plurality of piezoelectric beams to be different, 5 to 11 sub-bands can be formed in the vocal frequency range (eg, 20 Hz-16000 Hz). In some embodiments, by adjusting the structural parameters of the plurality of piezoelectric beams to be different, 5 to 16 sub-bands can be formed in the vocal frequency range (eg, 20 Hz-16000 Hz). In some embodiments, by adjusting the structural parameters of the plurality of piezoelectric beams to be different, 6 to 24 sub-bands can be formed in the vocal frequency range (eg, 20 Hz-16000 Hz). It should be noted that the frequency range of the piezoelectric beam, the number of sub-bands, and the resonant frequency corresponding to each sub-band is not limited to the above description, and can be adapted according to the specific situation such as the application scene of the microphone and the size of the sensing device. adjustment, which is not further limited here.

In some embodiments, the output at the resonance peak of each piezoelectric beam is much larger than the output in other frequency ranges. By separately extracting the signals generated by each piezoelectric beam, sub-band frequency division of the full-frequency sound signal can be realized. In some embodiments, subsequent processing (eg, de-noising, amplitude modulation, etc.) may be performed on each subband, and after each separately processed subband signals are fused, a higher signal-to-noise ratio and more flat transmission can be obtained. The frequency response curve of the sensor device. In some embodiments, the electrical signals of each piezoelectric beam can be output to the processor in the form of electrical series or parallel or a combination of series and parallel, or the electrical signals of each piezoelectric beam can be output to the processor individually, and the processor The electrical signals of each piezoelectric beam 35211 are processed separately to achieve frequency band fusion. By arranging multiple piezoelectric beams in the sensing device and utilizing the characteristics of piezoelectric beams (for example, piezoelectric beams 35211) having different resonance frequencies, the filtering and frequency band decomposition of the vibration signal can be realized, avoiding the need for the use of piezoelectric beams in the sensing device. The complexity of the filter circuit and the software algorithm occupy high computing resources, which brings about the problems of signal distortion and noise introduction, thereby reducing the complexity and production cost of the sensing device.

In some embodiments, different piezoelectric beams can be set to increase resonance peaks in different frequency ranges, so as to improve the sensitivity of the sensing device near multiple resonance peaks, thereby improving the sensitivity of the sensing device in a wider frequency band.

In some embodiments, a surface of the second membrane structure 35213 may be connected to the side of the base body 3522 away from the bottom wall of the casing and cover the opening of the base body 3522, and a surface of the second membrane structure 352113 away from the base body is in contact with the liquid. In some embodiments, the second membrane structure 35213 may be connected to the side wall corresponding to the opening of the base body 3522 through its peripheral side, where the second membrane structure 35213 is adapted to the shape and size of the opening of the base body 3522 . In some embodiments, the shape of the second membrane structure 35213 may include, but is not limited to, regular shapes such as circles, rectangles, ellipses, semi-circles, polygons, etc., or any irregular shapes. By arranging the second membrane structure 35213, the liquid can be effectively prevented from flowing into another cavity through the gap between the piezoelectric beams or between the piezoelectric beams and the substrate, thereby effectively improving the reliability of the sensing device.

In some embodiments, the second membrane structure 35213 may be connected with the plurality of piezoelectric beams 35211 . In some embodiments, the second membrane structure 35213 may be connected with the peripheral side of the piezoelectric beam 35211 . In some embodiments, the second membrane structure 35213 may be connected to the side of the piezoelectric beam 35211 close to the base body 3522 . In some embodiments, the second membrane structure 35213 may be connected to the side of the piezoelectric beam 35211 away from the base body 3522 . Considering that the second membrane structure 35213 will hinder the vibration of the piezoelectric beam connected to it, in some embodiments, in order to reduce this effect as much as possible, the material of the second membrane structure 35213 can be selected to have a smaller Young's modulus, such as The pattern modulus of the barrier structure 33213 should be smaller than the Young's modulus of the electrode layer or the piezoelectric layer. In some embodiments, the material of the second film structure 35213 may include, but is not limited to, one or more of semiconductor materials, metal materials, metal alloys, organic materials, and the like. In some embodiments, the semiconductor material may include, but is not limited to, silicon, silicon dioxide, silicon nitride, silicon carbide, and the like. In some embodiments, metallic materials may include, but are not limited to, copper, aluminum, chromium, titanium, gold, and the like. In some embodiments, metal alloys may include, but are not limited to, copper-aluminum alloys, copper-gold alloys, titanium alloys, aluminum alloys, and the like. In some embodiments, the organic material may include, but is not limited to, polyimide, parylene, PDMS, silica gel, silica gel, and the like.

FIG. 36A is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device 3600A shown in FIG. 36A is substantially the same as that of the sensing device 2500 shown in FIG. 25 , and the main difference is that the transducer unit is different. The casing 3610A and the pipe structure 3650A shown in FIG. 36A are similar in structure to the casing 2510 and the pipe structure 2550 shown in FIG. 25 and will not be repeated here. As shown in FIG. 36A , the sensing device 3600A may include a housing 3610A and a transducing unit. The housing 3610A has a accommodating cavity inside, and the transducing unit is arranged in the accommodating cavity. The front cavity 3630A and the rear cavity 3640A on opposite sides of the vibrating structure. The transducer unit includes a capacitive transducer 3623A, and the capacitive transducer 3623A includes a back plate 36231A with holes and a diaphragm 36232A.

In some embodiments, the transducing unit may further include a base body 36212A, where the base body 36212A is similar to the base body 2522 shown in FIG. 25 , and details are not described herein again. Capacitive transducer 3623A may cover the open arrangement of substrate 36212A. The perforated back plate 36231A is arranged approximately parallel to the diaphragm 36232A. In some embodiments, a washer 36233A is disposed between the perforated back plate 36231A and the diaphragm 36232A to space them apart. The diaphragm 36232A may cover the opening of the base body 36212A. In some embodiments, the side of the diaphragm 36232A close to the base 36212A can be connected to the side of the base 36212A away from the bottom wall of the housing 3610A. The back electrode plate 36231A with holes is arranged in the opening of the base body 36212A, and the peripheral side of the back electrode plate 36231A with holes can be connected with the inner wall of the opening. In some embodiments, when the cavity near the diaphragm 36232A is filled with liquid, the liquid contacts the diaphragm 36232A. Liquid cannot flow between the diaphragm 36232A and the perforated back plate 36231A. When the capacitive transducer 3623A receives the vibration signal, the vibrating membrane 36232A vibrates so that its distance from the perforated back plate 36231A changes, thereby generating an electrical signal. In some embodiments, the material of the diaphragm 36232A and the material of the perforated back plate 36231A may be conductive materials (eg, copper, aluminum, graphite, etc.). In some embodiments, the diaphragm 36232A can be a non-conductive polymer elastic film, and at least one side of the polymer elastic film is plated with a conductive layer (for example, an aluminum film layer), and the material of the perforated back plate 36231A can be conductive material. Exemplarily, the material of the polymer elastic film may include, but is not limited to, polyethylene terephthalate (PET), polycarbonate (PC), vinyl polymer (PVC), acrylonitrile-butadiene- One or more of styrene copolymer (ABS) and polyethylene (PE).

In order to reduce the Q value of multiple resonance peaks and resonance valleys on the frequency response curve of the sensing device, the structure of the sensing device shown in FIG. 36B is proposed on the basis of FIG. 36A . FIG. 36B is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device 3600B shown in FIG. 36B is substantially the same as that of the sensing device 2500 shown in FIG. 36A , and the main difference is that the installation methods of the capacitive transducers are different. Housing 3610B, front chamber 3630B, rear chamber 3640B, duct structure 3650B, base 36212B, perforated back plate 36231B, diaphragm 36232B and gasket 36233B shown in Figure 36B are the same as housing 3610A, front chamber shown in Figure 36A 3630A, rear cavity 3640A, pipe structure 3650A, base 36212A, back plate 36231A with holes, diaphragm 36232A and gasket 36233A are similar in structure, and will not be repeated here. As shown in Figure 36B, the cavity near the perforated back plate 36231B is filled with liquid, the liquid is in contact with the perforated back plate 36231B, and can penetrate into the perforated back plate 36231B through the holes in the perforated back plate 36231B Between the diaphragm 36232B and the diaphragm 36232B, the overall damping of the capacitive transducer 3623B can be increased, so as to realize the damping adjustment of the sensing device, so as to achieve the purpose of smoothing the frequency response curve. In addition, after the inflow of the liquid, a dielectric layer is formed between the diaphragm 36232B and the back plate 36231B. By selecting the type of liquid, the parameters such as the dielectric constant of the electrostatic structure can be adjusted, and the efficiency of the electric signal generated by the capacitive transducer can be improved. In some embodiments, the pores on the perforated back plate 36231B can be made smaller so that the pores have a confinement effect on the liquid. In this way, the space between the perforated back plate 36231B and the diaphragm 36232B may not be completely filled with liquid, and there is still a partial air domain, thereby realizing the adjustment of the resonant frequency (eg, the first resonant frequency f0) of the capacitive transducer .

FIG. 37 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensor device 3700 shown in FIG. 37 is substantially the same as that of the sensor device 2500 shown in FIG. 25 . The structure of the transducer unit and the pipe structure 3750 shown in FIG. 37 is similar to the structure of the transducer unit and the pipe structure 2550 shown in FIG. 25 , and details are not described here. As shown in FIG. 37 , the sensing device 3700 may include a housing 3710, a transducing unit, and a piping structure 3750. The piping structure 3750 is located at the top of the housing 3710 in the direction of gravity, and the transducing unit is arranged in the accommodating cavity to pick up vibrations. The structure 3721 divides the accommodating cavity into a front cavity 3730 and a rear cavity 3740 located on opposite sides of the vibration pickup structure 3721, and the front cavity 3730 is filled with liquid.

In some embodiments, there is no confinement structure within the conduit structure 3750 at the liquid and gas interface. At this time, due to the viscous effect of the liquid itself, a gas-liquid interface with extremely low stiffness is formed between the liquid and the gas on the outside of the pipeline structure, and the overall additional stiffness of the liquid to the transducer unit is small, thus achieving a large output. In addition, the gas-liquid interface makes the resonance system corresponding to the pipeline structure have less rigidity, thereby providing a resonance peak with a smaller resonance frequency for the transducer unit, and improving the low-frequency response of the sensing device.

FIG. 38 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device 3800 shown in FIG. 38 is substantially the same as that of the sensing device 2500 shown in FIG. 25 , and the difference between the two is that the sensing device 3800 shown in FIG. 38 further includes a first membrane structure 3860 . The structure of the transducer unit and the pipe structure 3850 shown in FIG. 38 is similar to the structure of the transducer unit and the pipe structure 2550 shown in FIG. 25 , and will not be repeated here. As shown in FIG. 38 , the sensing device 3800 may include a housing 3810 , a transducer unit and a pipe structure 3850 , the transducer unit is arranged in the accommodating cavity, and the vibration pickup structure 3821 separates the accommodating cavity to be located opposite to the vibration pickup structure 3821 Front chamber 3830 and rear chamber 3840 on both sides, the front chamber is filled with liquid.

The first membrane structure 3860 is located between the liquid in the conduit structure 3850 and the gas outside the housing. In some embodiments, the first membrane structure 3860 is disposed in the pipe structure 3850, and the first membrane structure 3860 is connected with the inner wall of the pipe structure 3850 through its peripheral side. Specifically, the first membrane structure 3860 is used to isolate liquid and gas, and form a constraint for the liquid in the pipe structure 3850 to better prevent the liquid from overflowing the pipe structure. In addition, the stiffness provided by the first membrane structure 3860 can adjust the resonant frequency of the resonant system formed by the liquid and gas, improving the frequency response of the sensing device 3800. In some embodiments, the structure and material of the first membrane structure 3860 can be designed to adjust the resonance position of the additional resonance system formed by the liquid and the air cavity introduced into the sensing device 2500 and the resonance position of the transducing unit, so as to achieve High-sensitivity sensing devices under confined liquid boundaries. In some embodiments, the first membrane structure 3860 may be a membrane-like structure with flexibility (eg, high yield limit, no high temperature deterioration, etc.) and flexibility (eg, low hardness, easy deformation, etc.). Exemplarily, the first film structure 3860 can be selected from polyimide film (Polyimide Film, PI film), polydimethylsiloxane film (Polydimethylsiloxane, PDMS film), polyurethane (polyurethane, PU), polyether ether ketone (polyether ether ketone) One or more of poly(ether-ether-ketone), PEEK), semiconductor flexible film, silicone adhesive, silicone film, silicone gel, damping adhesive (eg, acrylic damping adhesive), and the like. In some embodiments, the thickness of the first membrane structure 3860 may range from 0.05mm to 0.15mm.

The adjustment of the frequency response curve of the sensing device can be achieved by constraining the liquid in the pipeline structure to different degrees. 39 is a frequency response curve of a sensing device according to some embodiments of the present specification. As shown in Figure 39, the abscissa represents the frequency, in Hertz Hz, and the ordinate represents the sensitivity, in volts decibels dBV. The curve 391 is the frequency response curve of the sensing device without the liquid and the pipeline structure, and the curve 392 is the frequency response curve of the sensing device with the liquid and the pipeline structure and the pipeline structure does not constrain the liquid (that is, a gas-liquid interface is formed between the liquid and the gas in the pipeline structure). The frequency response curve of the sensing device, the curve 393 is the frequency of the sensing device with a liquid and a pipeline structure and the pipeline structure has less constraint on the liquid (ie, the pipeline structure has a first membrane structure 3860 between the liquid and the gas). sound curve. Compared with curve 391, curve 392 and curve 393 have a larger output improvement. It can be seen that the sensitivity of the sensing device with liquid and pipeline structure can be greatly improved compared with the sensing device without liquid and pipeline structure. The positions of the resonance peak and resonance valley of the curve 392 are different from those of the curve 393. It can be seen that by changing the degree of restraint at the interface between the liquid and the gas in the pipeline structure, the resonance peak and the resonance valley corresponding to the resonance system corresponding to the pipeline structure can be effectively changed. Location. In some embodiments, the sensing device includes a plurality of conduit structures. In order to better adjust the position of the resonance peak that each pipe structure can provide, a first membrane structure 3860 for separating liquid and gas can be provided on part of the pipe structure, and the liquid and gas can form a gas-liquid interface in some pipe structures.

FIG. 40 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device shown in FIG. 40 is substantially the same as that of the sensing device shown in FIG. 25 , and the main difference is that it further includes a first gas cavity 4060 . The structure of the transducer unit and the pipeline shown in FIG. 40 is similar to the structure of the transducer unit and the pipeline shown in FIG. 25 , and will not be repeated here. As shown in FIG. 40 , on the outside of the pipe structure, another casing 4050 forms a first gas cavity 4060 . The front cavity 4030 is filled with liquid, the first gas cavity 4060 is disposed close to the front cavity 4030 and away from the rear cavity 4040 , and the first gas cavity 4060 communicates with the front cavity 4030 . In some alternative embodiments, the first gas chamber 4060 may be formed by the housing 4010, that is, the housing 4010 and the housing 4050 may be integrally formed housing structures. At this time, the "exterior of the housing" described elsewhere in this specification can be understood as being relative to the exterior of the housing structure constituting the front cavity or the rear cavity described in this specification. For example, when the casing 4010 and the casing 4050 are integrally formed, the first gas cavity 4060 can be regarded as the outside of the casing 4010. At this time, the duct structure connects the accommodating cavity formed by the casing 4010 with the outside of the casing 4010, namely The first gas chamber 4060 communicates.

In some embodiments, a gas-liquid interface may be formed between the gas in the first gas chamber 4060 and the liquid in the front chamber 4030 . In some embodiments, there may be a membrane structure between the gas in the first gas chamber 4060 and the liquid in the front chamber 4030 for isolating the gas and the liquid. In some embodiments, by increasing the gas cavity in communication with the liquid, the compressibility of the gas can be reduced, thereby increasing the equivalent stiffness of the resonance system corresponding to each pipe structure. In this case, each pipe structure may provide a higher frequency resonance peak than if the first gas cavity 4060 is not provided.

In some embodiments, the first gas chamber may also communicate with the rear chamber when the rear chamber is filled with liquid. At this time, a membrane structure for isolating the gas and the liquid may or may not be provided between the gas in the first gas chamber and the liquid in the back chamber.

FIG. 41 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device shown in FIG. 41 is substantially the same as that of the sensing device shown in FIG. 25 , and the main difference is that it further includes a second gas chamber 4160 . The structure of the transducer unit and the pipeline shown in FIG. 41 is similar to the structure of the transducer unit and the pipeline shown in FIG. 25 , and will not be repeated here. As shown in FIG. 41 , on the side of the casing 4110 away from the pipeline structure, another casing 4120 forms a second gas cavity 4160 , the front cavity 4130 is filled with liquid, and the second gas cavity 4160 is close to the rear cavity 4140 and away from the front The cavity 4130 is provided, and the second gas cavity 4160 communicates with the rear cavity 4140 . The second gas cavity 4160 is communicated with the back cavity 4140, which can increase the volume of the back cavity of the sensing device, thereby reducing the equivalent stiffness of the vibration pickup structure, so that the first resonant frequency moves to the low frequency direction, thereby improving the performance of the sensing device. Frequency response for low frequency bands. In some embodiments, the second gas cavity 4160 may be any shape, such as a cube or the like. In some alternative embodiments, the second gas chamber 4160 may be formed by the housing 4110, that is, the housing 4110 and the housing 4120 may be integrally formed housing structures.

FIG. 42 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device shown in FIG. 42 is substantially the same as that of the sensing device shown in FIG. 25 , and the main difference is that the housing is further provided with air holes. The structure of the transducer unit and the pipeline shown in FIG. 42 is similar to the structure of the transducer unit and the pipeline shown in FIG. 25 , and will not be repeated here. As shown in FIG. 42 , the front cavity 4230 is filled with liquid, and the air hole 4241 is arranged at the position of the casing 4210 corresponding to the rear cavity 4240 , and the air hole 4241 communicates the rear cavity 4240 with the outside world.

In some embodiments, the front cavity 4230 is filled with liquid, and one or more air holes 4241 are provided at the position of the housing 4210 corresponding to the rear cavity 4240 . The air hole 4241 connects the rear cavity 4240 with the outside, which can be regarded as increasing the volume of the rear cavity of the sensing device, thereby reducing the equivalent stiffness of the vibration pickup structure, and moving the first resonant frequency to the low frequency direction, thereby improving the sensing device’s performance. Frequency response for lower frequency bands. In some embodiments, the air holes 4241 may have any shape, such as circular, square, or triangular.

FIG. 43 is a schematic structural diagram of a sensing device according to some embodiments of the present specification. The overall structure of the sensing device shown in FIG. 43 is substantially the same as that of the sensing device shown in FIG. 42 , and the main difference is that the air holes are covered with a third membrane structure. The structure of the transducer unit and the pipeline shown in FIG. 43 is similar to the structure of the transducer unit and the pipeline shown in FIG. 25 , and will not be repeated here. As shown in FIG. 43 , the front cavity 4330 is filled with liquid, the air hole is arranged at the position of the casing 4310 corresponding to the rear cavity 4340 , and the air hole is covered with a third membrane structure 4342 .

In some embodiments, the third membrane structure 4342 can isolate the gas in the back cavity 4340 from the outside gas. In some embodiments, the third membrane structure 4342 is connected to the housing 4310 near the side of the housing 4310 . In some embodiments, the peripheral side of the third membrane structure 4342 is connected to the air hole wall. In some embodiments, the peripheral side of the third membrane structure 4342 is connected to the inner wall of the rear cavity 4340 . In some embodiments, the shape of the third membrane structure 4342 may include, but is not limited to, regular shapes such as circles, rectangles, ovals, semi-circles, polygons, etc., or any irregular shapes. In some embodiments, the material of the third film structure 4342 may include, but is not limited to, one or more of semiconductor materials, metal materials, metal alloys, organic materials, and the like. Compared with the structure of FIG. 42 , the third membrane structure 4342 forms a rigid constraint on the gas in the rear cavity 4340 , thereby improving the equivalent rigidity of the vibration pickup structure, making the first resonant frequency move to the high frequency direction, thereby increasing the The frequency response of the sensing device at higher frequencies. In some embodiments, when the peripheral side of the third membrane structure 4342 is connected to the wall of the air hole, the shape of the third membrane structure 4342 can be adapted to the shape of the air hole.

It should be noted that the above description of the sensing device is only an exemplary description, and does not limit the description to the scope of the illustrated embodiments. For example, the first gas chamber and the liquid-filled chamber may communicate through a connecting channel. For another example, the third membrane structure may be a planar membrane structure or a three-dimensional membrane structure (eg, an airbag).

It should be noted that different embodiments may have different beneficial effects, and in different embodiments, the possible beneficial effects may be any one or a combination of the above, or any other possible beneficial effects.

The basic concept has been described above. Obviously, for those skilled in the art, the above detailed disclosure is only an example, and does not constitute a limitation to the present application. Although not explicitly described herein, various modifications, improvements, and corrections to this application may occur to those skilled in the art. Such modifications, improvements, and corrections are suggested in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

Meanwhile, the present application uses specific words to describe the embodiments of the present application. Such as "one embodiment," "an embodiment," and/or "some embodiments" means a certain feature, structure, or characteristic associated with at least one embodiment of the present application. Therefore, it should be emphasized and noted that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places in this specification are not necessarily referring to the same embodiment . Furthermore, certain features, structures or characteristics of the one or more embodiments of the present application may be combined as appropriate.

Furthermore, unless explicitly stated in the claims, the order of processing elements and sequences described in the present application, the use of numbers and letters, or the use of other names are not intended to limit the order of the procedures and methods of the present application. While the foregoing disclosure discusses by way of various examples some embodiments of the invention presently believed to be useful, it is to be understood that such details are for purposes of illustration only and that the appended claims are not limited to the disclosed embodiments, but rather The requirements are intended to cover all modifications and equivalent combinations falling within the spirit and scope of the embodiments of the present application. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described systems on existing servers or mobile devices.

Similarly, it should be noted that, in order to simplify the expressions disclosed in the present application and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of the present application, various features are sometimes combined into one embodiment, in the drawings or descriptions thereof. However, this method of disclosure does not imply that the subject matter of the application requires more features than those mentioned in the claims. Indeed, there are fewer features of an embodiment than all of the features of a single embodiment disclosed above.

Some examples use numbers to describe quantities of ingredients and attributes, it should be understood that such numbers used to describe the examples, in some examples, use the modifiers "about", "approximately" or "substantially" to retouch. Unless stated otherwise, "about", "approximately" or "substantially" means that a variation of ±20% is allowed for the stated number. Accordingly, in some embodiments, the numerical parameters set forth in the specification and claims are approximations that can vary depending upon the desired characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and use a general digit reservation method. Notwithstanding that the numerical fields and parameters used in some embodiments of the present application to confirm the breadth of their ranges are approximations, in particular embodiments such numerical values are set as precisely as practicable.

Each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., cited in this application is hereby incorporated by reference in its entirety. Application history documents that are inconsistent with or conflict with the content of this application are excluded, as are documents (currently or hereafter appended to this application) that limit the broadest scope of the claims of this application. It should be noted that, if there is any inconsistency or conflict between the descriptions, definitions and/or terms used in the attached materials of this application and the content of this application, the descriptions, definitions and/or terms used in this application shall prevail .

Finally, it should be understood that the embodiments described in the present application are only used to illustrate the principles of the embodiments of the present application. Other variations are also possible within the scope of this application. Accordingly, by way of example and not limitation, alternative configurations of embodiments of the present application may be considered consistent with the teachings of the present application. Accordingly, the embodiments of the present application are not limited to the embodiments expressly introduced and described in the present application.

Claims

A sensing device comprising:

a housing, the housing has an accommodating cavity inside;

The transducer unit includes a vibration pickup structure for picking up the vibration of the casing to generate an electrical signal, and the transducer unit is separated in the accommodating cavity to form a front cavity and a rear cavity located on opposite sides of the vibration pickup structure a cavity, wherein at least one of the front cavity or the rear cavity is filled with a liquid that is in contact with the vibration pickup structure; and

One or more conduit structures, each conduit structure configured to communicate the containment cavity with the exterior of the housing, the liquid at least partially located in the one or more conduit structures.
The sensing device according to claim 1, wherein the resonance system corresponding to the one or more pipe structures causes the sensing device to generate at least one resonance peak and resonance valley.
The sensing device according to claim 2, wherein the vibration pickup structure has a first resonance frequency, and the resonance frequency of the resonance system corresponding to at least one of the one or more pipe structures is lower than the first resonance frequency.
The sensing device according to any one of claims 1-3, wherein the one or more duct structures comprise a plurality of duct structures, and the cavity volumes of the plurality of duct structures are different.
The sensing device of any one of claims 1-4, wherein a gas-liquid interface is formed between the liquid in the one or more conduit structures and the gas outside the housing.
4. The sensing device of any one of claims 1-4, comprising a first membrane structure between the liquid in the one or more conduit structures and the gas outside the housing .
The sensing device according to any one of claims 1-6, wherein the vibration pickup structure comprises a piezoelectric film, and the transducer unit further comprises a base body, and the base body is a structural body with an open opening, The piezoelectric film covers the opening of the base body, and an end of the base body facing away from the piezoelectric film is connected to the housing.
The sensing device according to claims 1-6, wherein the vibration pickup structure comprises a plurality of piezoelectric beams, and the transducer unit further comprises a base body, the base body is a structure body with an open opening, each The piezoelectric beams are respectively connected with the base body and extend toward the center of the opening.
The sensing device according to claim 8, wherein the plurality of piezoelectric beams have the same structure and are symmetrically distributed along the geometric center of the opening.
The sensing device of claim 8 or 9, comprising a blocking structure that fills or covers the gaps between the plurality of piezoelectric beams.
The sensing device according to claim 8 or 9, wherein a gap between two adjacent piezoelectric beams in the plurality of piezoelectric beams is not greater than 20um.
The sensing device according to any one of claims 1-6, wherein,

The transducer unit further includes a base body, and the base body is a structural body with an open opening;

The vibration pickup structure includes: a plurality of piezoelectric beams, the plurality of piezoelectric beams are distributed at intervals at the opening; and a second membrane structure, the second membrane structure covers the opening of the base body, so One end of the base body facing away from the second membrane structure is connected to the casing.
13. The sensing device of claim 12, wherein the plurality of piezoelectric beams vibrate to generate resonance peaks of different frequencies.
The sensing device according to any one of claims 1-6, wherein the transducer unit comprises a capacitive transducer, and the capacitive transducer at least comprises a perforated back plate and a diaphragm.
15. The sensing device of claim 14, wherein the capacitive transducer further comprises a washer located between the back plate and the diaphragm to separate the back plate from the diaphragm. Describe the diaphragm spacing setting.
16. The sensing device of claim 15, wherein the liquid is capable of infiltrating between the perforated back plate and the diaphragm through holes in the perforated back plate.
17. The sensing device of claim 16, wherein an air domain exists between the perforated back plate and the diaphragm.
The sensing device according to any one of claims 1-17, wherein the housing further has a first gas cavity, one of the front cavity and the rear cavity is filled with the liquid, and the first gas cavity is filled with the liquid. A gas chamber communicates with the liquid-filled chambers in the front chamber and the rear chamber.
The sensing device according to any one of claims 1-17, wherein the housing further has a second gas cavity, one of the front cavity and the rear cavity is filled with the liquid, and the first cavity is filled with the liquid. The second gas chamber communicates with the front chamber and the other chamber in the rear chamber which is not filled with the liquid.
The sensing device according to claims 1-17, wherein one of the front cavity and the rear cavity is filled with the liquid, and the front cavity and the rear cavity are not filled with the liquid An air hole is provided at the position of the shell corresponding to the other cavity of the device.
The sensing device of claim 20, wherein the air hole is covered with a third membrane structure.